608 
DIPTERA. 
though it approaches the latter in its structure, and in its 
sluggish habits. 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 (Stratiomyadje) are 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, hut 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 
larva) 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, 
when the enclosed insects change to pupae ; 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 become 
pupa). Some of the soldier-flies ( Stratyomys ) have a broad 
oval body, ornamented with yellow triangles or crescents 
on each side of the hack, and their antennae are somewhat 
like those of Midas and of the gad-flies ; others ( Sargus ) 
are slender, often of a brilliant brassy-green color, with a 
bristle on the tip of their antennae. The maggots of the 
latter live in rich mould. 
The Syrphians (Syrfhida:) have a fleshy, large-lipped 
proboscis, elbowed near the base, and enclosing only four 
* Canadian Naturalist, p. 199. 
