﻿AXTHOMYIIDAF. TACHINIDAE 



507 



Portschinsky, lays a small number of very large eggs, and the result- 

 ing larvae pass from the first to the third stage of development, 

 omitting the second stage that is usual in Eumyiid Museidae. 1 



Fam. 35. Tachinidae. — First posterior cell of wing nearly or 

 quite closed. Squamae large, covering the halteres: antennal arista 

 hnr>>: upper surf ace of body usually bristly. This is an enormous 

 family of flies, the larvae of which live parasitically in other living 

 Insects, Lepidopterous larvae being especially haunted. Many 

 have been reared from the Insects in which they live, but beyond 

 this little is known of the life-histories, and still less of the structure 

 of the larvae of the Tachinidae, although these Insects are of the 

 very first importance in the economy of Nature. The eggs are 

 usually deposited by the parent-flies near or on the head of the 



Fig. 2-12. — Ugimyia sericariae. A, The perfect fly. x 3 : B, tracheal chamber of a silk- 

 worm, with body of a larva of Ugimyia projecting; a, front part of the maggot 

 b, stigmatie orifice of the maggot ; c, stigma of the silkworm. (After Sasaki.) 



victim ; Riley supposed that the fly buzzes about the victim and 

 deposits an egg with rapidity, but a circumstantial account given 

 by Weeks 2 discloses a very different process: the fly he watched 

 sat on a leaf quietly facing a caterpillar of Datana engaged in 

 feeding at a distance of rather less than a quarter of an inch. 

 " Seizing a moment when the head of the larva was likely 

 to remain stationary, the fly stealthily and rapidly bent her 

 abdomen downward and extended from the last segment what 

 proved to be an ovipositor. This passed forward beneath her 

 body and between the legs until it projected beyond and nearly 

 on a level with the head of the fly and came in contact with the 

 eye of the larva upon which an egg was deposited," making an 

 addition to five already there. Ugimyia sericariae does great 



1 Baron von Osten Sacken informs the writer that this statement has since beeE 

 withdrawn by Portschinsky as being erroneous. 



2 Eat. Amcr. iii. 18S7, p. "126. 



