194 ZOOLOGY. 
The Midaside contain a number of very large Diptera with clubbed 
antenne. Midas filatus (black, with a transverse orange band near the 
base of the abdomen) inhabits the United States. 
Leptis (fig. 116) is the representative of a family (Leptide) of small flies 
of varied colors. In this genus the head is depressed, the antennee end in 
a bristle, and the thorax is tuberculate. 
The ArTHERIcERA contain the four families Syrphide, in which the labium 
incloses four sete ; Conopside, Muscide, having two sete; and Cstride, 
with the mouth obsolete. | | 
The Syrphide are tolerably large variously colored flies, which move 
swiftly through the air, and often hover over a spot for some time without 
changing their position. They have a hemispherical head, a great part of 
which is taken up by the eyes, a soft rostrum elbowed towards the base, 
with a pair of lip-like expansions at the tip, and the palpi small and 
inarticulate. 
The genus Volucella (VY. pellucens, pl. 77, fig. 111) is remarkable 
for its resemblance to the genus Bombus (bumble bee), which was 
designed to enable it to reach without suspicion the nests of the 
latter, in which the larve are parasitic, feeding upon the larve of 
the bees. 
The eggs of Syrphus are deposited among the Aphides, upon which the 
larve feed. Other larve are vegetable feeders, and those of Hristalis (E. 
tenax, fig. 114) and Helophilus (fig. 115) are aquatic, and have the pos- 
terior part of the body attenuated into a breathing tube. These leave the 
water to transform in the ground. Sceva pyrastri (fig. 112), Chryso- 
toxum (fig. 113). 
The family Conopside (Conops macrocephala, fig. 90) are parasitic in the 
nests of bees in the larva state, and the imagos frequent flowers. Latreille 
reared a species which was parasitic in bees, and we have met with a living 
grasshopper in Pennsylvania, with the abdomen filled with several dipterous 
larvee which we did not succeed in rearing. They may have belonged to 
this genus, or to Tachinus. Latreille placed the genus Stomozxys (S. calct- 
trans, fig. 91) in this family. . 
The family Muscide (figs. 101, 103, 106, 108) is very extensive, and 
contains many minor groups. The habits of the species are very various. 
Sarcophaga carnaria (fig. 109) deposits its larvee upon rotten vegetables, 
caterpillars, and even on earthworms, which they penetrate, leaving their 
posterior extremity at the surface. Several genera deposit their eggs upon 
flesh the moment it has become tainted; and Tachina and allied genera 
resemble the Ichneumonide in being parasitic in other living insects. 
Musca domestica, the house fly, accompanies civilized man in his migra- 
tions. The transformations of this species are said to take place in dung. 
Various larve attack different kinds of fruits, roots, and branches, causing 
galls, and decaying vegetable matter of different kinds. The larva of 
Piophila casei ( fig. 103) infests cheese, and that of P. petasionis is found 
in preserved hams. Both are known as skippers. The larve of Oscanis 
and Chlorops are destructive to growing grain. 
398 
