123 



DIPTEROUS PAKASITES — TACHINID^. 



There are a number of species belonging* to this family of flies 

 which are parasitic on the bollworm. The female fly deposits her 

 eggs on the surface of the body of the larva, generally toward the 

 anterior end. Sometimes but a single egg is laid, although a parasi- 

 tized larva frequently bears several eggs attached to it. The eggs are 

 of a pearly white color Avhen first laid, but often turn darker when the 

 embryo begins to develop in them. The}^ are somewhat less than a 

 millimeter in length, elongate in shape, with rounded ends and paral- 

 lel sides. As soon as the egg hatches, the parasitic grub bores into the 

 bollworm through the skin and begins feeding upon its fatty tissue, 

 undergoing a very rapid growth. Even when a number of eggs are 

 attached to a single larva, it is rare for more than one parasitic grub 

 to mature in the bollworm. 



The species of the family resemble each other so closely that it is 

 almost impossible for an^^one not familiar with them to recognize the 

 different forms. The table below gives a summary of the species bred. 



Table XLIX. — Species of Tachmidse hredfrom bollworms during 1903 and 1904- 



Name. 



Locality. 



Date. 



Food plant of 

 bollworm. 



Winthemia U-pustulata Fab 



Exorista ceratomix Coq 



Euphorocera claripennis JVIacq . 

 Gonia capitaia De G 



Do 



Archytas piliventris v. d. W. . . . 



Do 



Paris, Tex 



Calvert, Tex.. 



Paris, Tex 



Ladonia, Tex. 



Paris, Tex 



Victoria, Tex. 

 do 



Aug. 

 Sept. 

 Aug. 

 Nov. 

 Nov. 

 May 

 May 



22, 1904 



4. 1903 

 18,1904 



2. 1904 

 7, 1904 



26, 1903 

 29, 1903 



Alfalfa. 

 Cotton. 

 Alfalfa. 



Do. 



Do. 

 Com. 



Do. 



Of these it is probable that the first is most valuable in northern 

 Texas, and the last mentioned (see fig. 25) in the southern part of the 

 State. 



In addition to this list the following 

 species are known to be parasitic on the 

 bollworm, although they were not bred 

 by us during the past two seasons: 

 Frontina armigera Coq., F. frenchii 

 Will., and F. aletice Riley. The first 

 was bred b}^ Coquillett^'^ from bollworms 

 collected at Los Angeles, Cal. ; the second 

 by Riley ^, and the last by Trelease^. 



Early in November a lot of eighty- 

 seven larva?, mostly full-sfrown, were ^ „, , . .,. . . ,. ^ 



' • r Fig. 25. — Archytas piliventris: adult fly 



collected by Mr. Girault in an alfalfa (original). 



field at Paris, and forty of them, or nearly 50 per cent, bore tachinid 



fly 6^gs on their bodies. . One had as many as eleven, but most of 



« Insect Life, J, p. 331. 



& Fourth Missouri Rept. p. 129, footnote. 



Fourth Rept. U. S. Ent. Com., p. 377. 



