608 DIPTERA. 



though it approaches the latter in its structure, and in its 

 sluggish hahits. The larva) or maggots, though not yet 

 discovered, undoubtedly live in the ground, or in decayed 

 vegetable substances, like those of the horse-flies and other 

 predatory insects ; for Mr. Gosse found one of his specimens, 

 on the grass, in the act of emerging from the pupa-skin. 

 He has also figured * the pupa, which is of a chestnut-brown 

 color, and has transverse rows of spines on the abdominal 

 rings. 



Most of the soldier-flies (Stratiomyad.e) arc armed with 

 two thorns or sharp spines on the hinder part of the thorax. 

 They form the first family of the flies that undergo their 

 transformations within the hardened skin of the larva, which 

 is not thrown off till they break through it to come out in the 

 winged state. Their proboscis contains, at most, only four 

 bristles, is not fitted for piercing, but ends with large fleshy 

 lips, by means whereof these flies suck the sweet juices of 

 flowers. Most of them are found in wet places, where their 

 larv£e live ; some of the latter being provided with a tube, 

 in the hinder extremity, which they thrust out of the water 

 in order to breathe. The skin of these larvae is merely 

 shortened a little, without wholly losing its former shape, 

 Avhen the enclosed insects change to pupa; ; thereby showing 

 that this family is truly intermediate between the preceding 

 flies, which cast off their larva-skins, and those which retain 

 them, and take an oblong oval shape, when they becoma 

 pupas. Some of the soldier-flies (^Stratyomys) have a broad 

 oval body, ornamented with yellow triangles or crescents 

 on each side of the back, and their antennas are somewhat 

 like those of Midas and of the gad-flies ; others (^Sargus) 

 are slender, often of a brilliant bi'assy-green color, with a 

 bristle on the tip of their antennae. The maggots of the 

 latter live in rich mould. 



The Syrphlans (Syrphidjj:) have a fleshy, large-lipped 

 proboscis, elbowed near the base, and enclosing only four 



* Canadian Naturalist, p. 199. 



