THE SILKY ASILUS. 
605 
These insects belong to a family called Asiliile, from 
Asilus, the principal genus. In the larva state, those of the 
Asilians whose habits are known live in the ground upon 
the roots of plants, and sometimes do considerable mischief, 
as proved to be the case with some that were sent to me last 
May, by the Rev. Thomas Hill, of Waltham, who found 
them devouring the roots of the tart rhubarb. They were 
yellowish-white maggots, about three quarters of an inch 
long, not perfectly cylindrical, but a little depressed, and 
tapering at each end. The head was small, brown, and 
partially drawn within the first ring, and was provided with 
two little horny brown hooks. There was a pair of breath- 
ing-pores on the first ring, and another pair on the last hut 
one. These maggots were transformed in the earth to naked 
pupaj, having the limbs free. The pupa was brown, and 
had a pair of short horns on the forehead, three spines on 
each side of the head, a forked tail, and a transverse row 
of little teeth across the middle of each ring of the hind 
body. When about to undergo their last transformation, 
the pupae work their way to the surface of the ground by 
the help of the little teeth on their rings. I have repeatedly 
seen the empty pupa-shells sticking half-way out of the 
ground around rhubarb plants. In the fore part of July, 
there issued from these pupse some 
long-bodied flies, which proved to 
be of the species called Asilus se- 
riceus (Fig. 265) by Mr. Say. 
The body of this insect is slender 
and tapering, and measures from 
eight tenths of an inch to one inch 
and one tenth in length. It is of 
a brownish-yellow color, covered 
with a short silky down, varying 
in different lights from golden yel- 
low to brown, and with a broad brown stripe on the top 
of the thorax. The wings are smoky brown, with broad 
