Chemical control of Chironomid larvae was investigated in the two different rivers, Zenpukuji and Nogawa, of Tokyo. The River Zenpukuji with a moderate current was treated with temephos W. P. for 60min at 1ppm. Seven days after the treatment, larval population was reduced by 80% in the area from the treatment spot to the 500-meter point downstream, and by less than 70% at the 900-meter point downstream. However, number of the 1st-instar larvae resurged 10 days after treatment. The River Nogawa (Koganei City, Tokyo) was treated with temephos W. P. for 60min at 1ppm. Four days after the treatment, there was no larval population of midge in the area from the treated spot to the 3,100-meter point downstream, but young instar larvae resurged 8 days after the treatment. One month after the treatment, the larval population was larger than the pre-treatment period. The second test in the same river with 0.68-ppm treatment for 60min resulted in inferior control, which is considered to be attributable to the differences in chemical concentration and to the low temperature (24℃ vs. 19℃). Within several hours after the treatment, a great number of the larvae and pupae were carried away, and most of them were found dead. All the larvae intoxicated were observed to die in 72hrs under the laboratory conditions. However, some portion of the larvae which survived in mud tubes after the treatment, emerged into adults.

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A new genus, Tokunagayusurika, is created in the subfamily Orthocladiinae, with Orthocladius akamusi (Tokunaga, 1938) as a monotypic member. This species is quite unique both in morphology and biology as a chironomid. The body size is much larger than other members of the subfamily, and is almost as large as the giant midge, Chironomus plumosus (L.). The larvae are blood red in color, and are found in the bottom mud of eutrophicated lakes. The adults emerge once a year in late autumn. The structure of male genitalia, especially the shape of the style, is highly complicated and does not fit to any of the known genera. The adults are also unusual in that they lack in the comb on the apex of hind tibia. Morphological characters of pupae and larvae are newly described. This species is considered as to be playing a significant role in fixing and removing organic nutrients from eutrophicated lakes, but causes a serious nuisance during the season of its emergence.

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The resistance level of the 15 strains of houseflies collected from the Philippines were examined against 6 insecticides, DDT, pyrethrins, malathion, fenitrothion, fenthion, and dichlorvos. Most colonies showed higher susceptibility against these insecticides than the Takatsuki strain, especially to DDT. The LD_<50> values of malathion were between 0.0975μg per fly. Among the 15 strains, 7 showed higher LD_<50> values against malathion than the Takatsuki strain. These results mean that the houseflies in the Philippines are increasing their resistance against malathion.

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Using light trap (black light), night catches of some Japanese black flies were made in southern part of Kyushu, Japan, during the years 1975-1977. Light traps were set and operated weekly or daily for varying periods at different places : A-cowshed in mountainous area, E-dwelling house in a sparsely populated district in the city, both places being 2km from the nearest breeding sites, B-cowshed in a pasture infested with bovine Onchocerciasis in a mountainous area, C-pigsty in a rural area, and D-poultry farm in the suburbs of the city, where two to six species of simuliids were found breeding in streams within 500m from the trapping sites. In the cowshed (A), of which the structure of the wall prevented the light of trap from escaping outwards, a total of 268 females belonging to 6 species were collected during three years from 1975-1977. The 268 females included 143 Simulium (Simulium) japonicum, 57 S. (Odagmia) aokii, 29 S. (S.) arakawae, 21 S. (S.) rufibasis, 15 S. (Gnus) bidentatum and 3 S. (S.) quinquestriatum. All species contained blood-fed females in different ratios from 23.8 to 46.7% of the total, but neither gravid female nor male individual. In another cowshed (B), which was roughly built, lacking walls on south and north sides, thus permitted the light of the trap to extend outwards to a considerable distance from the cowshed, a total of 108 adults were captured by 10 trappings from June to September 1977. Species and the number of flies trapped were S. (S.) japonicum 84,S. (S.) arakawae 11,S. (Eusimulium) uchidai 5,S. (G.) bidentatum 4,S. (S.) rufibasis 3 and S. (S.) quinquestriatum 1. Of these, 10 S. (S.) japonicum, 2 S. (S.) arakawae, 2 S. (G.) bidentatum and 1 S. (E.) uchidai were males. And, of 93 females captured, 22-100% of blood-fed females were found in S. (S.) japonicum, S. (S.) arakawae, S. (S.) rufibasis and S. (G.) bidentatum, and 23-100% of gravid females in all species except for S. (G.) bidentatum. In the pigsty (C), 10 trappings between February and June 1975,yielded 10 black flies consisting of 3 S. (E.) uchidai, 2 S. (E.) aureohirtum, 2 S. (S.) arakawae, 1 S. (G.) bidentatum, 1 S. (S.) japonicum and 1 S. (S.) nikkoense. Two of these were male individuals, belonging one to S. (E.) uchidai and one to S. (G.) bidentatum. One of 2 S. (S.) arakawae was engorged with blood. A single blood-fed female of S. (E.) uchidai was trapped in the poultry (C) by 34 weekly night collections from April to October 1977,and also one unfed female of S. (S.) arakawae in the dwelling house (E) by 115 light trappings from September 1976 to August 1977. From these results, some ecological aspects of adult black flies in southern part of Kyushu were revealed as follows : 1) Females of S. (O.) aokii, S. (G.) bidentatum, S. (S.) arakawae, S. (S.) japonicum, S. (S.) rufibasis and S. (S.) quinquestriatum fly to the cowshed at least 2km from their breeding sites, presumably feed on cattle, even at night and then fly away sooner or later before they become gravid. 2) A light trap operated near breeding places captured males as well as females of the same species as found by the previous collections of the immature stages, suggesting that flight range of male individuals of some black flies is confined to the area not far from their habitats. 3) The seasonal span of both S. (S.) japonicum and S. (S.) arakawae in the trap in the cowshed (A) was from the middle of May to the beginning of November and that of S. (O.) aokii and S. (S.) rufibasis from the middle of May to the late of August. 4) A marked decrease in the number of females per night trapped in the cowshed (A) between 1975 and 1977 was considered mainly due to the construction work of the new highway which destroyed many breeding places for the aquatic stage of black flies. 5) S. (S.) japonicum was supposed to be a vector of Onchocerca gutturosa, a parasite of bovine Onchocerciasis prevailing in the pasture (B).

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The effects of waters conditioned by the egg rafts or the larvae of Culex pipiens molestus and C. tritaeniorhynchus summorosus on their intraspecific oviposition preference were investigated. Preference was shown to the water on which egg rafts of the same species had been floated for one day at 20℃ over tap water in C. p. molestus, but not in C. tritaeniorhynchus. When the number of egg rafts was over ten in water conditioning, the oviposition females of C. p. molestus discriminated between the conditioned water and tap water. C. tritaeniorhynchus was reluctant to choose the water which had contained the 1st-instar larvae for only one hour at 25℃, but this effect was trivial with the water in which the 4th-instar larvae had been held. However, the oviposition females of C. p. molestus showed a significant preference to the water which had contained the over thirty 4th-instar larvae in 200ml for one hour at 25℃. Even if two 4th-instar larvae had been contained per pot for one day, but not one hour, the water was selected by C. p. molestus. However, no clear discrimination was made by C. p. molestus between tap water and the water which had contained the 1st-instar larvae for one hour at 25℃. The water in which larvae were reared from the 1st-instar to pupation at 25℃ was preferred for oviposition over tap water in both species. This difference in the experimental results for C. tritaeniorhynchus may be attributed to the food present in the microbiota rich, larvae-rearing water. The interpretation of these results was made in connection with the larval adaptability to the density and the ecological characteristics of larval habitat in each species.

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The effects of temperature on the development of larval and pupal stages, the interspecies competition in larvae, and the effects of temperature on the fecundity of three species of fleshflies, B. peregrina, P. similis and P. crassipalpis, were studied under the laboratory conditions. The larvae were reared on minced beef, and adults were fed on milk and 2% sucrose solution. Minced beef was given as a larviposition medium. The results were obtained as follows : 1. The length of larval stage was shorter than that of pupal stage in all species. The length of development from the larva to adult emergence, was shortest in P. similis, followed by B. peregrina and P. crassipalpis. 2. The calculated developmental zero points and accumulated thermal constants of the larval and pupal stages in three species are shown in Table 2. 3. The notable differences of the body weight of these pupae were observed when the larvae were reared under 20℃. The pupal weight of P. crassipalpis was about two times as that of B. peregrina. 4. Two species were introduced into the breeding medium at different rates, and three combinations of flies were set up to interact. The competition was estimated from the difference of percents of adult emergence between two species. With the increased number of B. peregrina, the percent of adult emergence of P. similis decreased. Similarly, with the increased number of P. similis, the percent of adult emergence of P. crassipalpis decreased. 5. The favourable temperatures for fecundity lay at 25℃ in B. peregrina, between 20 and 30℃ in P. similis, and between 25 and 30℃ in P. crassipalpis, B. peregrina proved to be superior in the reproduction, capacity to the other two species.

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The epidemiological study was made on the cases of black fly bites in the campus of a certain college of Kanagawa prefecture during the period from February 1976 to January 1977,where many students had been suffered from various skin lesions by black fly bites and six kinds of black flies including the dominant species of Simulium aokii were identified from the nearby stream. The patients of 85 individuals were recorded among 200 students in total during one year survey. Black fly bites were observed in all seasons, but most of the bites occurred in three months from May to July. Most of the bites were inflicted around sunrise or sunset, especially from 3 to 5 p.m. Most of the bites occurred in the fields such as the farm or the lawn around the campus but a few cases were recognized indoor such as the green house or the passage of the school building. The sites of bites were present mainly at the upper or lower extremities. Many lesions and accompanying manifestations produced by black fly bites were recognized. Redness as primary lesions was classified into four types : erythema, point-sharp erythema, erythema nodosum and urticarial rash. These reactions occurred within 15min in most cases but the occurrence of 24hrs later was also observed. While, erythema nodosum and urticarial rash developed into secondary lesions including eczematous purulence or necrosis. In this study, severe cases including fever, nausea, headache, lymphnode swelling or general malaise were recognized. Their manifestations may suggest the participation of allergic reaction for the toxin of black flies. The duration of the scar of black fly bites was common in 4 or 5 days, but also in one year or so.

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Arachnidism caused by the genus Chiracanthium has been reported from subtropical or warm temperate zones in all over the world. So far in Japan, total 50 cases of arachnidism caused by C. japonicum, which is recognized to be most dangerous, were recorded and analized epidemiologically from the medical points of view up to 1976. The investigation was made on the function and the histology of the venom apparatus for the purpose of analysing the cause of arachnidism. The venom apparatus is associated with the chelicerae or first pair of appendages of the cephalothorax. Each consists of a large basal segment and a terminal claw-like fang piecerced by the duct from the venom gland. The fang of male is about two times longer than that of female, therefore, the fangs of male was found to be able to penetrate the palmar skin of volunteer more deeper than that of female. The muscularis was found to cover the whole gland beginning from the neck of the gland. This is the bundle of fibers of striated-muscle. The basement membrane from a continuous layer under the muscularis. The two kinds of epithelial cells were observed lining the basement membrane. The first layer is formed by small and low cells with an ovarial nucleus. The second layer is formed by high columnar cells attaching on the basement membrane. Both the nuclei of the first and the second cells show the same morphological structure by the optical microscopy.

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Endoparasitic mites on anatid birds were investigated. The survey was carried out in Shinhama, Chiba prefecture and in Koshigaya, Saitama prefecture during the period from November, 1967 to February, 1968. The total of 489 anatid birds consisted of 6 species were examined. 1) Two species of nasal mites, which have not been reported in Japan, were collected from the anatid birds. These were Rhinonyssus rhinolethrum (Trouessart, 1895) and Trispeleognathus womersleyi (Fain, 1955). 2) The six species of host birds examined were pintail, Anas acuta acuta Linne, 1758; teal, Anas crecca crecca Linne, 1758; wigeon, Anas penelope Linne, 1758; shoveller, Anas clypeata Linne, 1758; spot-billed duck, Anas poecilorhyncha zonorhyncha Swinhoe, 1866 and mallard, Anas platyrhynchos platyrhynchos, Linne, 1758. In addition, domestic ducks were examined in the two different places of the survey. 3) Rhinonyssus rhinolethrum was collected from 169 birds of 489 examined (34.6% of infestation rate), which were distributed to all 6 species in the survey. The infestation rate of wigeon by this mite was highest (73.5%). These of pintail, teal, shoveller, spot-billed duck, and mallard were 40.5%, 20.6%, 17.6%, 11.1% and 2.2% respectively. Trispeleognathus womersleyi was collected only from pintail and mallard. Their infestation rates were 16.4% and 4.4% respectively. 4) Majority of pintail and wigeon were found to be infested by less than 5 mites of Rhinonyssus rhinolethrum or Trispeleognathus womersleyi if infested. 5) Of the 171 domestic ducks examined, 84 were used as decoy birds, among which 8 were found to be infested by nasal mites. The rest of the domestic ducks were found not to be infested by them.

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Atylotus hasegawai, a new species, was described on the basis of adult and larval materials collected from Tohoku Province of Honshu Island, Japan. This species is quite allied to A. horvathi (Szilady) and A. bivittateinus Takahasi. Although it is very difficult to distinguish these three allied species by a single morphological character, the bilogy of the present species is quite different from the other two. Main morphological differences among them are discussed in this paper.

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The mosquito fish, Cambusia affinis (Baird and Girard) was introduced into Tokushima city in 1968 to control mosquito larvae in the salt marsh and the drains. Thereafter the fish propagated and spread into the wide area of the city. In the present study, it was clarified how extent they were distributing in the city area after 8 years since the introduction. The distribution of G. affinis in the winter season were limited. During several years following the introduction, the fish were spread by the members of laboratory. However it was confirmed by the present study that the fish spread themselves from the focus of the distribution to the surrounding areas during the spring and summer time. In the autumn of 1975,G. affinis distributed approximate 70 percent of the water bodies, whereas, larvae of Culex pipiens pallens distributed in the limited places. The effectiveness of G. affinis on the control of mosquito larvae was studied by releasing the fish into the drains where only Culex pipiens pallens larvae were inhabiting. After average 250 individuals of G. affinis per drain of approximately 2m×80m were released, the number of mosquito larvae decreased at 7 drains out 9. The fish settled in the these places and could be observed till four months later when the experiment was ended. The effectiveness of G. affinis on the mosquito control was studied also by examining the number of adult mosquitoes. Light traps were set up at the G. affinis densely inhabited area and the no G. affinis area. Comparison of the number of mosquito between the two areas indicated no significant difference. Mosquitoes seemed to be not abundant even in the area where no G. affinis inhabited in the present study.

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Preliminary studies on the interval between two successive blood meals of Aedes (Stegomyia) polynesiensis, the main vector of subperiodic bancroftian filariasis in the South Pacific, were undertaken by two methods : one, by mark-and-release experiments in Fiji, and the other, by the size of developing filarial larvae in the mosquitos from Tuvalu. The results obtained by both methods were similar, and the average blood meal interval in the field was estimated to be three or four days under the temperature range 25-31℃. The latter method is considered to be useful for estimation of blood meal interval of vector mosquitos in endemic areas of filariasis.

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Venom was extracted from venomous spicules of the Oriental tussock moth caterpillar, Euproctis subflava, and its pharmacological and biochemical properties were investigated. 1. Pharmacological activities such as positive skin reaction in man, increase in vascular permeability and contraction of smooth muscle of the isolated guinea pig ileum, and deformation of goat erythrocytes (EDA) were demonstrated in the venom extracted with PBS (pH 7.2). 2. The crude venom was separated into two, high molecular (HM) and low molecular (LM) fractions, by a single hollow fiber concentrator with a cut-off molecular weight of 15,000. Thin-layer and paper chromatographies revealed the presence of histamine in the LM fraction as identified by close agreement in Rf values and developed colors. 3. HM and LM fractions were further fractionated by column chromatography on Sephadex G-100 or G-50,respectively. HM fraction was separated into 4 (HM-I-IV) fractions : HM-I, which was eluted in the void volume, showed EDA. HM-II and III were proved to contain potent proteolytic (casein as substrate) and esterolytic (tosyl-arginine methylester, TAME as substrate) activities, respectively. Kinin-producing activity was also found in HM-III. Furthermore, ileum contraction activity was demonstrated in HM-II-III and IV, and all of the 4 fractions were positive in skin reaction and caused increase in vascular permeability. 4. On the basis of these results, it is suggested that the local reactions caused by the venomous spicules in the human skin are due to toxic substance(s) and/or enzyme(s) contained in the spicules rather than to mechanical injury.

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Scanning electron microscopy revealed that the spines of the slug moth caterpillar, Parasa consocia had no opening at the pointed ends, differing from the results reported by many investigators based on light microscopic observations. Fine structure of the spicules and their sockets on the 8th and 9th dorsal segments of the last instar larva was also described. PBS extracts from the spines and spicules were fractionated by a single hollow fiber concentrator (SHFC). The inner fluid in SHFC, containing substances with molecular weights higher than 15,000 (HM) was further fractionated through a Sephadex G-100 column, while the outer fluid containing lower molecular substances (LM) was fractionated through a Sephadex G-50 column. 1. Injection of crude venom from the spines and spicules into the tail vein of mice made them squeak and bite at the injected area due probably to local pains, followed by crouching posture and shiver for a few hours. Paralysis was observed at their hind legs when injected with the venom subcutaneously. 2. Thin-layer chromatography revealed the presence of histamine in both the venoms from the spines and spicules. 3. HMs and LMs separated from the crude venoms of the spines and spicules exhibited positive skin reactions in man by scratch method : Erythema and edema or wheal were the common symptoms produced by all of these fractions tested. Severe recurrent pains were produced by the HMs a few minutes after application. The pains were relieved within several hours, but contact stimuli to the applied area of the skin produced the recurrent pains for a few days. Though the LM from the spine venom also showed pain-producing activity, it differed from the HMs in its rapid action and shorter duration. 4. Each of the HMs from the spine and spicule venoms was separated into 3 fractions (HM-I-III), by column chromatography : HM-Is had a wheal producing activity in the skin test. HM-IIs had activities to produce severe pain and to contract smooth muscle of the isolated guinea pig ileum. The contraction induced by the two HM-IIs differed from that by histamine in that the former took longer time before the onset and showed longer duration of the contraction after several washes with Tyrode's solution; it also differed from the contraction caused by bradykinin in that the former showed tachyphylaxis. Moreover, self-movement of the ileum was increased during or after the contraction and it continued till the intra-ileac contents were thoroughly ejected. Contraction activity of the spine HM-II might be due to two substances, HM-IIa and HM-IIb. Stimulating effect of the spine HM-II on the polymodal receptor of dog testis was kept longer than that of bradykinin. Vascular permeability in guinea pig skin was also increased by the spine HM-I-III. 5. The LM from the spines was found to contain two active substances; one was histamine and the other was protein or polypeptide (LM-I) with a molecular weight of several thousands. LM-I possessed activities such as pain-producing, ileum-contracting without tachyphylaxis, and vascular permeability-increasing. From these results, it was suggested that LM-I might be a kinin-like substance.

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It is known that tumor-like lesions of the alimentary canal have been experimentally induced in cockroaches and locusts by nerve severance, duct ligation, decapitation, etc. The similar lesions have been known to occur spontaneously in less than 10 percent of these insects in nature. We have recently found the same kind of lesion in more than 80 percent of our laboratory colony of Periplaneta fuliginosa (Serville). The roaches bearing the lesion were abnormally distended or swollen in their abdomens filled with whitish fat bodies. At autopsy, this lesion was easily recognized as a white opaque mass against the normal brownish tissue. Histologically, tracheation and pigmented necrotic foci were seen in the lesion, and around it hundreds of hemocytes aggregated to give an appearance of tumor. The nuclei of the peripheral cells were located near the inner bound-aries, but no mitosis was observed. These figures suggest that the lesion is not of neoplasmic nature but a sort of repairing process of injury; we now regard it as a kind of ulcer. Field surveys conducted around Nagoya City in 1975-1976 revealed that the overall mean incidence of the lesion among the natural populations of P. fuliginosa was about 17 percent. But it differed by the collection sites, ranging from 3 to 65 percent. It did not noticeably change by the seasons of the year. However, the morbidity in the female (ca. 34%) was significantly higher than those in the male (ca. 13%) or larva (ca. 12.5%). Laboratory rearing of the cockroaches collected in nature seemed to increase their morbidity up to 90 percent or more, and the high morbidity resulted in high mortality with little exceptions. This tendency was more definitely shown when the roach was reared individually.

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Affected by successive use of fenthion and dichlorvos houseflies inhabiting the third "Yumenoshima, " a dumping-island in Tokyo Bay have developed high multiresistance to organophosphorus compounds. In 1975-1977 maximum resistance ratios, R/S at LD50,were : fenthion, 428; dichlorvos, 79; fenitrothion, 2,224; diazinon, 1,042; malathion, 982. However, the cross-resistance to prothiophos was low with R/S 2 at LD50. The high OP pressure given in the field likely did not involve resistance to pyrethroids.

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Various artificial substrates for immature simuliid were compared to establish a standard quantitative sampling method. And a hand collection method were also investigated. The artificial substrates used were nylon scrubbing brushes, short and long polyvinyl chloride (PVC) sheets, PVC tubes, fire bricks, normal bricks, and ceramic tiles. The number of simuliids captured by the PVC tubes was largest and that by the nylon scrubbing brushes was smallest. The hand collection were carried out by two collectors for five minutes each. In order to collect the immature stages of simuliid quantitatively, use of two methods, PVC tubes and five-minute collection are recommended.

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Eight sampling methods of adult black flies were compared at Shuzenji, Shizuoka Prefecture. Of these methods, those which could obtain a good number of flies were sweeping with nets, sticky ribbon hanging close to a stream and light traps set at a cowshed. Sweeping with nets and sticky traps were suitable for collecting males. However, light traps were more effective for mass collection of female Simulium aokii and S. bidentatum, both the blood-fed and unfed. S. aokii showed its maximum activity from just after sunset to midnight, S. bidentatum, on the other hand, showed its maximum activity after midnight until one or two hours before sunrise.

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This is a report of the human cases of tick infestation which occurred in the northern part of Honshu during the years 1972-1977. These included 18 sporadic cases by hard ticks, a mass case of old rehabilitating patients with Argas japonicus, another mass case with A. vespertilionis at a shrine, and also 67 cases of students with Ixodes acutitarsus who investigated animal habitats in mountains of Shimokita Peninsula. Moreover, it is the first record in Japan that the larvae of I. acutitarsus were collected by flagging method in the same area.

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