﻿94 NINTH ANNUAL REPORT 



is squarely docked off, and contains two small yellowish-brown, eye- 

 like spots, which are the principle spiracles or breathing pores. • 



These small maggots are found in the locust egg-pods, either 

 singly or in varying numbers, there sometimes being a dozen packed 

 together in the same pod. They exhaust the juices of the eggs and 

 leave nothing but the dry and discolored shells, and where they are 

 not numerous enough to destroy all the eggs in the pod, their work,. 

 in breaking open a few, often causes all the others to rot. 



When fed to repletion this maggot contracts to a little cylindrical, 

 yellowish-brown pupa, (Fig. 23, h) about half the length of the out- 

 stretched and full-grown larva, and rounded at both ends. From this 

 pupa, in the course of a week in warm weather, and longer as the 

 weather is colder, there issues a small, grayish, two-winged fly, (Fig. 

 23, a) about ^ of an inch long, the wings expanding about ^ of an inch, 

 and in general appearance resembling a diminutive house-fly, except 

 that the body is more slender and more tapering behind, and the 

 ■vyings relatively more ample. More carefully examined, the body is 

 seen to be of an ash-gray color, tinged with rust-yellow, and beset 

 with stiff' bristle-like hairs, those on the thorax stoutest, and those on 

 the abdomen smaller but more uniformly distributed. The wings are 

 faintly smoky and iridescent. There are three dusky longitudinal 

 stripes on the thorax, most distinct anteriorly, and another along the 

 middle of the abdomen, most distinct in the male, which also differs 

 from the female in the larger eyes, which meet much more closely on 

 the top of the head than in the female, and in the face being whiter. 



The Winter is passed mostly in the pupa state, though doubtless 

 in some cases also in the winged state. 



The flies of this genus are characterized by the shoitness of the 

 antennae, and by the attenuated abdomen. The characters given to 

 it are, however, by no means uniform, and as the species generally 

 bear a very close resemblance to each other, and there have been a 

 large number described in Europe, (many of them very imperfectly), 

 it becomes almost an impossibility to properly determine them. As 

 the sexes often differ materially, it is also, except where they are 

 reared from the larva, difficult to connect them, and a§ the colors often 

 become sordid and dull in the cabinet, many of the described species 

 have no real existence. 



The flies frequent flowers, and often congregate and play in swarms 

 in the air. Their eggs are white, smooth, oval, about 0.01 inch long, 

 and are dropped near the food of the larva. In the larva state these 

 insects mostly feed on leguminous plants, and the carnivorous habit 

 is exceptional. The species affecting the Cabbage, the Onion, the 



