3 o8 



THE STUDY OF INSECTS 



■CL> 



Fig. 541. 



The proboscis is usually short, only a few members of the family having 

 it long like the bill of a snipe. The wings are broad, and when at rest are 

 held half open. The empodia are pulvilliform (Fig. 541). 



The flies are usually of moderate size. They may be found 

 about low bushes and on tall grass. They are sometimes slug- 

 gish and, therefore, easily caught. 



Large masses of these flies have been observed in various 

 parts of this country ; and formerly, in the far West, they 

 were collected by the Indians and used for food after being 

 cooked. It is said that as many as a hundred bushels of flies 

 could be collected in a single day. 



The larvae of this family are found in various situations; 

 some live in water, but a larger number live in earth, in decaying wood, 

 or in sand. 



Family Acrocerid^; 



The Small-headed Flies 



These flies are easily recognized by the unusually small head, the 

 large humpbacked thorax, the inflated abdomen, and the very large 

 alulets (Fig. 542). The body is devoid of bristles and the empodia are 

 pulvilliform. 



The head is composed almost entirely of eyes, and in 

 some genera is minute. The eyes are contiguous in both 

 sexes or nearly so. The antennae are three-jointed, and 

 are furnished with a style or an arista in some genera, in 

 other genera the style and arista are absent. 



The flies are generally slow and feeble in their movements. In some 

 species that feed upon flowers the proboscis is very long, sometimes ex- 

 ceeding the body in length. Other species take no nourishment in the 

 adult state, and have no proboscis. 



The larvae of only a few members of this family have been observed; 

 these are parasitic in the egg-sacs or in the bodies of spiders. 



Fig. 542. — Plero- 

 dontia misella. 



Family Bombyliid^; 



The Bee-flies 



These flies are mostly of medium size, some are small, others are 

 rather large. In some the body is short and broad and densely clothed 

 with long, delicate hair (Fig. 543). Other species resem- 

 ble the horse-flies somewhat in appearance, especially 

 in the dark color or markings of the wings; but these 

 can be distinguished from the horse-flies by the form of 

 the antennae and the venation of the wings. 



The antennae are usually short; they are three- 

 jointed and with or without a style. The ocelli are 

 present. The proboscis is sometimes very long and 

 slender, and sometimes short and furnished with fleshy lips at the extremity. 

 The adult flies feed on pollen and nectar, and are found hovering 

 over blossoms, or resting on sunny paths, sticks or stones; they rarely 

 alight on leaves. The larvae are parasitic infesting hymenopterous and 

 lepidopterous larvae and pupae and the egg-sacs of Orthoptera. 



Fig. 543. — Bombylius. 



