Over 5 years surveys on the food habits of 'Habu', poisonous snake, in nature in the Amami Islands were carried out since September of 1959 and the results were summarized as follows : 1. 927 cases were examined and these animals as food of Habu in nature belong in 43 species, 38 genera and 27 families of whole classes of Vertebrata, i. e. 85.9% of them belonged in Mammal, 6.6% of birds, 4.9% of Reptile, 2.5% of Amphibia and 0.2% of Pisces. 2. 17 species of animals were newly found as the food of Habu. 3. House rats and water rats occupied of 82.5% of whole cases examined and the author believes that the house rat is very important one as the food of Habu. 4. Main food of young snake was cold-blooded animals as Reptile and that of adult was warm-blooded animals, especially house-rats. 5. Rats occupy majority of food all year round but the rate of bird becomes higher in autumn. 6. Territory of Habu varies in wide range from field to around residence area and Habu likes house rats so much that residence area must be dangerous zone of chance of Habu attack. 7. Nocturnal activity of Habu and its activity of climbing tree and invasion to residence were proved by its food habits. 8. Sizes of food vary by size of snake and sometimes its takes same size of food as its own body length. 9. Foods are swallowed from head and also digested from there. 10. New knowledges on taxonomy and ecology of food animals were obtained from these series of surveys.

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筆者の一人である榊原は栃木県宇都宮の放牧地において条虫類の中間宿主となるササラダニ類の調査中であるが, その際に新種とみなすべきササラダニの一種を見出した。本種はマルツチダニ科(新称)Mochlozetidaeに属するもので, 筆者らはこれをPodoribates cuspidatus sp. n.と命名し記載した。本邦産のPodoribates属としては, すでに岸田がP. noyorii Kishidaを記載しているが, 今回見出された種とは胴感毛(sensilli)の形態によつて区別できる。現在のところ本種の体内からは条虫の擬嚢尾虫は発見されていない。

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Three species of Rhadinopsylla from Hokkaido and their hosts are reported. They are Rhadinopsylla (Actenophthalmus) japonica from Pteromys volans orii, Rhadinopsylla (Actenophthalmus) ohnoi and Rhadinopsylla (Actenophthalmus) alphabetica taken mainly from Clethrionomys rufocanus bedfordiae. The occurrence of R. ohnoi in Hokkaido is recorded here for the first time.

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1)主として関東地方において1960年頃よりビール麦倉庫の荷役人夫の間にダニによる皮疹が目立つてきている.筆者らは1965年9月29日, 最も被害の甚だしい茨城県下の4倉庫において被害の実体とダニ類の調査を行なつた.2) 皮疹の発生は毎年9月-11月に最も多く, 荷役後6-8時間で症状が現われている.症状発現までの時間がやや短いことを除いて米国におけるシラミダニによる被害にきわめて類似した点が多い.3) 見出されたダニ類は, シラミダニPyemotes uentricosus (Newport), アシナガツメダニCheletomorpha lepidoptorum (Shaw), アシボソオソイダニ(仮称)Cunaxa sp., フチドリイトダニ(仮称)Leiodinychus sp.の4種であつた.4) これらのうち, シラミダニとアシボソツメダニはきわめて個体数多く, 皮疹の主要原因とみなされる.アシボソオソイダニは個体数僅少, フチドリイトダニはその属する科の習性や食性から考えて皮疹の原因とはなりがたい.5) シラミダニの宿主およびアシナガツメダニの被捕食者となりうるものとして, 倉庫内に多数繁殖しているツヤコチャタテおよびコナチャタテ属の一種, さらにコクゾウムシや自活性ダニ類(フチドリイトダニなど)があげられよう.6)興味ある現像として, シラミダニは俵やかますの表面にほぼ均一に分散しているが, 一部のかます上に直径7-8cmのオレンジ色のシラミダニ群塊が見られた.また群塊が淡いピンク色の場合には半数以上のダニが死亡していた.この群塊の形成がなにを意味するかは不明である.7) ダニ類による被害発生の原因としては, 倉庫の構造上の不備(開放性, 土間床などの点), それに伴なうダニ類の栄養源としての昆虫類・ダニ類の侵入増殖, わらの使用, 薬剤散布・燻蒸の不徹底などが考えられる.

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広義のアカイエカCulex pipiens s.l.のmolestus型の実験室飼育系統から分離確立したgenetic markerを保有するGr系とOr系, およびanautogenous(pallens型)Ka系を用いて, 種々の交配実験をおこない, これらの系統の交尾選択性, 交尾習性等について検討した.1.Or系♀×(Or系♂+Gr系♂)の交配では, 全観察卵塊のおよそ13%に, 同一卵塊から由来する幼虫に, Or色と混合色MIXの幼虫の混在が認められ, これらの幼虫は, Or♀×Or♂とOr♀×Gr♂から由来し, GrとOrの2系統の♂の精子と受精した卵の集りから由来するとみなされた.従つて, 1匹の♀がOrとGrの両者の♂と交尾受精し, それぞれの精子と受精したものが混合することがあると推定された.2.Ka系♀×(Gr系♂+Ka系♂)ないしGr系♀×(Ka系♂+Gr系♂)の交配では, 得られた卵塊別のふ化率, 胎死率, 末熟率と, ふ化した幼虫の色によつて, これらの組み合せにおいても, Ka系およびGr系において1匹の♀が2匹ないし, それ以上の♂より受精することがあると推定された.3.(Gr系♀+Ka系♀)×(Gr系♂+Ka系♂)の交配では, Ka系♀にKa系♂とGr系♂の2系統の♂と交尾受精したと推定されるものが観察卵塊の6.3%に認められた.4.♂羽化1日前と8日前に羽化した2系統の♂が混在する場合は, Or系♀×(Or系♂+Gr系♂)ないしKa系♀×(Gr系♂+Ka系♂)およびGr系♀×(Ka系♂+Gr系♂)のいずれの組み合せでも, ♀の羽化1日前に羽化した若い♂と交尾受精する傾向が強いことが推定された.5.Ka系♀×(Ka系♂+Gr系♂), Gr系♀×(Gr系♂+Ka系♂), (Gr系♀+Ka系♀)×(Gr系♂+Ka系♂)の交配では, それぞれ同型同志との交尾選択性が明らかに認められた.

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1.チカイエカ型アカイエカの幼虫飼育条件とくに給餌量が, その成長, 成虫の大きさ, および無吸血産卵性にどのような影響を与えるかを調べた.この実験における飼育条件のもとで, 餌量を幼虫1個体当り2.5mg, 5.0mg, 10.0mg, 20.0mg, 40.0mgの5区作つたところ次のような結果をえた.2.成長は餌量が多い程速くなつた.幼虫期間は2.5mg/larva区で13.9日, 40.0mg/larva区で7.4日であつた.3.羽化率は中央の10.0mg/larva区が最高値79.6%を示した.4.無吸血産卵率は40.0mg区, 20.0mg区で100%を示し, 10.0mg, 5.0mgとなるに従い率は低下するが, 80%以下にはならない.最少量の2.5mg区の雌は3個体とも無吸血産卵性を示した.5.翅長は次の順で長くなる : ♂<非無吸血産卵性♀<無吸血産卵性♀.各群とも餌量が多い程翅長は大きい.

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わが国の4つの温泉地(蓮台寺, 浅間, 戸倉・上山田, 内郷)において, 温泉廃水を含む水体中に南米原産の胎生魚, グッピーが野生化し, 自然繁殖を続けていることを確認し, 主に戸倉・上山田および蓮台寺でグッピー個体群とその環境についての調査を行つた.グッピーは冬季には温泉廃水の混入する場所のみに生息する.これらの場所の水温は20℃前後に維持されている.戸倉・上山田温泉のこのような場所の一つで, グッピーは冬の終りには非常な高密度に達していた.しかし夏になるとグッピーは温泉の影響の少い農業用水, 水田, 川の岸辺の浅水部などへ広く分散する.この時期には越冬場所の個体数は著るしく減少した.これらのグッピーは下水の混入する汚濁のかなり強いところにも生息しうる.しかし耐寒性はない.グッピーの生長は非常に早く, 産子間隔も短いので, 急速に個体数が増加する.このような性質と強い雑食性によつて, 水田その他の水たまりの蚊幼虫の駆除にグッピーを利用することができる.調査した2つの温泉地の水田にはシナハマダラカとコガタアカイエカの幼虫が極めて少なかつた.

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Investigations were made to find out the cause of inactivation of some organophosphorous insecticides after mixed with polluted water. Fourth instar larvae of the mosquito, Culex pipiens pallens, DK strain, were used for test of the effectiveness of the insecticides. Results of experiments to expose the larvae at 28℃ for 24 hours to buffer solutions with various pH values have shown that 50% levels were 11.8 and 2.4 and no deaths were seen between pH 3 and pH 10. Further tests were made on the residual effects of insecticides mixed in buffer solutions with varying pH values from 3 to 10. At the observations made after 16 days, no considerable reduction in the effectiveness was seen for dieldrin, lindane, p-p' DDT, fenthion (Baytex), fenitrothion (Sumithion), parathion and methyl-parathion, while remarkable reductions in effectiveness were seen at all pH levels for ronnel, at alcaline solutions over 7 for dichlorovos (DDVP) and malathion, and at acid solutions below 4 for diazinon. The loss of activity of some insecticides when mixed with polluted water discussed below is therefore considered not due to the direct effect of hydrogen ion concentrations. Experiments were carried out to see the effects of bacterial growth in media containing insecticides. The insecticidal activity of parathion, methylparathion and fenitothion was found to be remerkably reduced or almost completely lost within 4 days when these were mixed into polluted water prepared with a animal food from natural environments or into unsterilized bacterial culture media such as 1.0% peptone solution. The media containing pure culture of Bacillus subtilis was found to cause the same inactivating effects on the insecticides, while the insecticidal activity was kept unchanged when these were mixed after the media had been sterilized. Both fenthion and diazinon were stable under the same condition and no reduction in the effectiveness was seen for a period of 16 days. The above inactivation of some insecticides in polluted waters was found to be due to bacterial decomposition of substances non-toxic or less toxic to the insects. For example, Bacillus subtilis was demonstrated to decompose parathion to amino-parathion, and fenitrothion to amino-fenitrothon or to methylparathion and further to aminomethylparathion. LC 50 levels against C. p. pallens larvae of amino-parathion, amino-methylparathion and amino-fenitrothion were estimated to be 5.37, 60.3 and 115 ppm., respectively. The chemical structures of amino-parathion, amino-methylparathion and amino-fenitrothion are O, O-diethyl O-para-aminophenyl phosphorothioate, and O, O-dimethyl O-(3-methyl-4-aminophenyl) phosphorothioate, respectively.

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A screening method of cockroach repellents was described. A filter paper (Toyo No.2., 10×9.6cm) impregnated with repellent at one prescribed concentration was set into a paper tube (10cm long by 3.0cm in diameter). The paper tubes were placed in a plastic cage (30×23×6cm), and then 50 adults of the German cockroach, Blattela germanica L., were released. Repellency was evaluated from number of the roaches in tube after 24 hours as follows; Repellency (%)={(Number of roaches in untreated tube)-(Number of roaches in treated tube)}×100/(Number of roaches in untreated tube).

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1965年6月から7月にかけて, 東京の夢の島に大発生し, 江東区南砂町に大移動して問題をひき起したイエバエの殺虫剤抵抗性について調べた.1.Topical applicationによる夢の島産イエバエ雌成虫の<LD>_<50>値を調べたところ, p, p′-DDT, γ-BHCのような塩素系殺虫剤に対して抵抗性が強いばかりでなく, malathion, diazinonに対しても極めて抵抗性の強いことが分つた.しかし, 同じ有機燐剤でも, DDVP, Baytex, Sumithionに対する交差抵抗性は低いことも分つた.2.夢の島コロニーの終齢幼虫の有機燐剤に対する<LC>_<50>値を求めたところ, malathion抵抗性は強いが, Baytex, Sumithion, DDVPはかなり有効なことが分つた.

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In order to know the contact toxicity of several insecticides against common millepede, Orthomorpha (K.) gracilis C. L. Koch, a seris of tests were carried out under laboratory conditions. Seven emulsions of insecticides, DDT, lindane, dieldrin, diazinon, DDVP, Baytex and Sumithion were tested through residue contact method using impregnated filter papers in various concentrations. As a result of the experiments, it was confirmed by LC-50 values after 24 hours of treatment that lindane is the most effective restult showing LC-50 value 2.3ppm and the others are successively effective in the following order : DDVP, diazinon, Baytex, Sumithion, dieldrin and DDT. LC-50 value of DDT was 1, 740 times of lindane emulsion.

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Effects of fenitrothion, malathion, lindane, dieldrin, diazinon, fenthion, chlordane and dichlorvos were evaluated by exposing Millipedes, Oxidus gracilis (Koch) to the residues of toxicants for 15 min., 1 hours or 7 days. The toxicants were applied with acetone solution containing 5% of the insecticides on filter paper at a ratio of 50ml per square meter. In these experiments the most effective insecticide was dichlorvos with the following in descending order : fenitrothion, diazinon, malathion and fenthion. Chlordane, lindane, malathion and dieldrin were found to be ineffective for the control of this pest.

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