Okabe. K., 1994. Inhibition of egg hatching of Histiogaster sp.(Acari:Acaridae)by shiitake mushrooms (Lentinus edodes) J. Acarol. Soc. Jpn., 3 (1) : 1-5. When eggs of Histiogaster sp. (Acari: Acaridae) were applied to a fungal colony of shiitake mushrooms, they were observed to become wrapped with a large number of hyphae. The hyphae grew rapidly under and around each mite egg and covered its surface heavily as if they had trapped it. No larva was observed on the fungal colony. This kind of reaction of hyphae against mite eggs has never been reported before in any other fungi. Key words:Histiogaster sp., shiitake mushroom, Lentinus edodes, mycophagous mite, mushroom pest

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The effect of photoperiod on host attachment activity and development of I. ovatus larvae and nymphs was observed at25°C under three photoperiodic conditions (10L-14D, 12L-12D and 16L-8D) . The host attachment activity of unfed larvae was hardly affected by photoperiod during the stages from egg to unfed larva, but that of unfed nymphs was slightly suppressed by exposure to a short-day photoperiod(10L-14D)during the stages from engorged larvae to unfed nymphs. The development of engorged larvae was little affected by the photoperiodic condition at which they were reared before, during and after engorgement. However, engorged nymphs entered diapause (lack of molting on 60 days after detachment) in the10L or 12L groups reared at 10L-14D or 12L-12D before, during and after engorgement. Irrespective of the photoperiodic condition at which the engorged nymphs were reared during and after engorgement engorged nymphs in the 16L group (reared at 16L-8D before engorgement) did not enter diapause. It seems that the diapause of engorged nymphs plays an important role in controlling the activity of I. ovatus adults.

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Hexane extract from a mixture of following astigmatid mites of all stages; Rhizoglyphus robini, Histiogaster sp. and Schwiebea sp, contained tridecane as the major components along with other non-hydrocarbon components, while the corresponding hypopodes contained a mixture of heptadecane, Z-8-heptadecene and Z, Z-6, 9-heptadecadiene as major components. Neryl formate, neral and geranial present in the extract of Schwiebea of all stages were also identified in the extract of the hypopus. In the other two species the non-hydrocarbon components detected in the developing stages were either minor components or not detected in the corresponding hypopodes. Survival of hypopus under dry conditions can be ascribed to the changes of hydrocarbons on the body surface from tridecane to a mixture of heptadecene and heptadecadiene.

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A new genus and species of podapolipid mite parasitic on Aethus indicus (Westwood) (Heterop-tera: Cydnidae) is described and illustrated from Southwest Japan under the name of Cydnipolipus miyamotoi. This is the first record of Podapolipidae from heteropteran insects. Cydnipolipus is compared with other podapolipid mites which have males with anterior aedeagi and females with 2 pairs of legs. It shares 13 apomorphic characters with Coccipolipus and Kurosapolipus.

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