DIPTERA 



851 



The larvae vary greatly in form and habits. Some prey upon plant 

 lice, and are often found in the midst of colonies of these insects ; some 

 feed in the stems of plants and in bulbs ; others feed on decaying vege- 

 table matter, and live in rotten wood, in mud and in water; and others 

 live in ordure or in decomposing animal remains. Some are found in 

 the nests of ants ; and some in the nests of bimiblebees and wasps. 



Among the common representatives of this family there is one 

 that so closely resembles a male honey-bee as to be often mistaken 

 for it. This is the Drone-fly, Enstalis tenax. It is common about 



/?. + 3 



Fig. 1 104. — WmgolEristaUs. 



flowers. The larva lives in foul water, where it feeds on decaying 

 vegetable matter; it is of the form known as "rat-tailed," which is 

 described below. 



The larvcB of the genus Volucella live as scavengers in the nests 

 of bimiblebees and of wasps {Vespa). Some of the species in the 

 adult state very closely resemble bimiblebees. 



The larvae of the genus Mtcrodon are hemispherical, slug-like 

 creatures (Fig. 1105), which resemble mollusks more than ordinary 

 maggots; they are common in ants' nests. 



The larvae of several species that live in water as well as some 

 that live in rotten wood are known as rat-tailed maggots on account 

 of the long, tail-like, appendage, with which the hind end of the body 

 is furnished. This is a tube, like that of a diver, which enables the 

 insect to obtain air when its body is submerged beneath several inches 

 of water or decaying matter. This 

 tube being telescopic can be length- 

 ened or shortened as the insect may 

 need it ; and at its tip there is a ros- 

 -'i^ m^l ette of hairs, which, floating on the 

 surface of the water, keeps the tip 

 Vig.iio^.-Microdo^t, adult from being submerged. The larva 

 and larva. has on the ventral side of its body Fig. 11 06.-. 



several pairs of tubercles armed with SyrpMis. 

 spines, which serve as prolegs. 

 Among the more common members of this family are the yellow- 

 banded species belonging to the genus Syrphus (Fig. 1 1 06) . The larvae 



