FLIES WHICH PARASITIZE THE WEEVIL. 47 



June 17, and reproducing June 19. On June 24 the third generation 

 was reproducing. In this case there were 11 days covering two com- 

 plete generations. 



The mites appeared willing to feed on any insect food available, 

 as they were lii'st found feeding on stages of Trichoharis compacta, 

 then on boll-weevil stages, and finally on a Baris, on boll-weevil 

 parasites isolated in rearing tubes, and on Ilydnocera puhescens. 

 They were reared readily on larvae of CJdorion cyaneum and Polistes 

 ruhiginosus. ^Ir. Jolm B. Railsb.ack, of Forbing, La., found that 

 they attacked the larvae of the bollworm and other smooth cater- 

 pillars very readily. 



TYROGLYPHID.E, 



Tyroglyphus hreviceps Banks was described as a weevil enemy 

 from Victoria, Tex. Tliis, or a similar mite, was found to be very 

 abundant at Calvert, Tex., in 1906. 



4. FLIES WHICH PARASITIZE THE BOLL WEEVIL. 



Very few Diptera are known to be primarily parasitic upon boll 

 weevils, but the genera Myiophasia and Ennyomma in the Tacliinidse 

 seem to be confined to hosts of tliis nature. The genus Apliiochseta, 

 of the Phoridse, contains at least 3 species wlxich have been reared 

 under circumstances pointing to primary parasitism. The larvae of 

 the tacliinids work singly and those of Apliiochseta several to a host, 

 but in both cases as endoparasites. Wlien the former become fuU 

 grown they completely fill the skins of the weevil larvae and fre- 

 quently the appendages of Myiophasia penetrate to the exterior. 

 The weevil skin partakes of the character of parchment and becomes 

 a cocoon witliin wliich the fly larva pupates and from wliich the 

 adult emerges. On the contrary the Apliiochaeta larvae leave the 

 host when they have reduced it to a shell and pupate in the weevil 

 ceU. 



The flies evidently prefer to attack weevil stages in moist, shaded 

 spots in preference to sunny locations. By tliis habit they become 

 very valuable in fields located in bottom lands wliere the diy condi- 

 tions conducive to parasites like the hjnnenoptcrous parasites are 

 absent. The puparia of Myiophasia and Ennyomma are so near 

 like that of the chalcidoid internal parasite Tetrastichus Tiunteri that 

 they can be differentiated only by the larger size of the dipterous 

 puparia. 



PHORID^. 



Apliiochseta nigriceps Loew (determined by D. W. Coquillett). 

 ApMochseta fasciata Fallen (determined by D. W. Coquillett). 

 ApMochseta pygmsea Zetterstedt (determined by D. W. Coquillett). 



