FLIES WHICH PAKASITIZE THE WEEVIL. 47 



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

 was reproducing. In this case there were 1 1 days covering two com- 

 plete generations. 



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

 as they were first 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 Hydnocera pubescens. 

 They were reared readily on larvae of CMorion cyaneum and Polistes 

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

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

 pillars very readily. 



TYROGLYPHID^. 



Tyroglyphus hreviceps Banks was described as a weevil enemy 

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

 abimdant 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 Tachinidse 

 seem to be confined to hosts of this nature. The genus Aphiochaeta, 

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

 under circumstances pointing to primary parasitism. The larvae of 

 the tachinids work singly and those of Aphiochaeta several to a host, 

 but in both cases as endoparasites. When the former become full 

 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 within which the fly larva pupates and from which the 

 adult emerges. On the contrary the Aphiochaeta 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 this habit they become 

 very valuable in fields located in bottom lands where the dry condi- 

 tions conducive to parasites like the hymenopterous parasites are 

 absent. The pup aria of Myiophasia and Ennyomma are so near 

 like that of the chalcidoid internal parasite Tetrastichus Jiunteri that 

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

 puparia. 



PHORID^. 



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

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

 ApJiiochseta pygmsea Zetterstedt (determined by D. W. Coquillett) , 



