64 NORTH AMERICAN DIPTERA. 



hovering motionless in the air for a time and darting away 

 like a ilash. They seek snnny places in woodland roads, 

 about blossoms or on rank vegetation. The Anthracinse are 

 a group especially characteristic of arid regions. In general 

 the members of the family are prettily and delicately marked, 

 and their life histories are often very interesting. In the 

 adult state they are flower flies, feeding upon the pollen and 

 honey deep within the blossoms, extracted by aid of their long 

 proboscis. The larvje of species of Ai^ha-hantus and Sijiita'chus, 

 occurring in western America, are found in the egg-pods of 

 the locust, Caloptenus spretus. "The larvae begin to trans- 

 form themselves into the pupa state early in the summer, and 

 the pupa pushes itself half way out of the ground in order to 

 disclose the fly. They continue to issue during the summer 

 months. As a ride but one year is required for full develop- 

 ment. Aphcebantiis is first observed as a yellowish white 

 grub, about half an inch long when extended, it being usually 

 curved so that the head and tail nearly meet. It is usiially 

 found in a case of locust eggs which it has devoured, pushing 

 the empty shells aside, and at last occupying the space where 

 were twenty-one to thirty-six eggs. Often it is found in a 

 little space below a number of egg-cases, as though it had 

 feasted off the contents of several nests" (Riley). The larvae 

 of Anthrax have been found parasitic upon 3Iegachile, Osniia, 

 Odynertis, Mamestra, Noctua and Agrotls ; tliose of Anji/ra- 

 ma'ha upon Pelopa-i(s, MegacliUe, Cemonns, Osiiiia and Callco- 

 doma ; those of Bomhijlms u])on Andrena and Colletes ; those 

 of Toxopliora upon Eumenes ; those of Callosto)iui in the egg- 

 cases of Cdlopteuiis ifatica'] those of Si/sfrojms upon Limd- 

 eodes, etc. 



TABLE OF GENERA. 



1. The hifurciitioii of the second iiiid tliird veins takes place opposite or 

 nearly ()pj)osite the anterior cross-vein, the distance not exceeding 

 the length of the cross-vein ; the second vein forms a knee at its 

 orijiin, the third vein in a straijiht line with the })refurca. . 2 



