826 
ANNUAL REPORT OP NEW TORN 
hessian fly. the female fly. the male fly. 
from the sheaths in which they are respectively enveloped _ a 
process analogous to that of withdrawing the hand and its sev¬ 
eral fingers from a tight glove— until at length entirely freed 
from its pupa skin, the fly, now perfect in all its parts, usually 
walks a few steps further up the straw, where it pauses for its 
body and members to acquire more firmness and strength by the 
further evaporation of their moisture, after which it is ready to 
spread its wings and mount into the air. 
In the female fly the head is black and of a flattened spherical form. Tho nntenn® are 
about half as long as the body, and composed of sixteen joints, which are separated from 
each other by very short translucent pedicels, which are about a third of the diameter of the 
joints. The joints are of a cylindric-oval form, their length being about double their thick¬ 
ness. Each joint is clothed with a number of hairs, of which those towards its base are per¬ 
ceptibly longer and coarser, about equalling the joint in their length, and placed in a low or 
whirl around it. Tho terminal joint is a third longer than those which preoede it; whilst tho 
two basal joints arc thicker than the others, globular, and compacj or not separated by an 
intervening pedicel. The palpi arc clothed with fine short hairs and are composed of three 
joints, of which the two last arc nearly equal in size, cylindrical, and about twice ns long an 
broad, the basal one being more short and thicker. The thorax is black, oval, and broadest 
immediately back of the wing sockets. The abdomen is elongate-ovate, its broadest part 
scarcely equalling the thorax in diameter. It is black on the back, with a tawny yellow or 
red band at each of the sutures, these bands varying in their width as the abdomen is more 
or less distended. Tho under side is obscure brownish ; but when the fly is newly hatched, it 
is bright red or yellow, with a blackish stripe along tho middle, in whioh stripe a small red 
or yellow spot is sometimes present upon the middle of each segment. The abdomen is 
clothed in plaoes with fine black hairs, and is composed of seven segments. When the sting 
or ovipositor is protruded, it forms two additional segments, of a pale red or yellow color; 
the apical one is a little tapering, thrice as long as broad, and is slightly dusky at its tip, tho 
end being blunt. Tho other is of the same length with the apical but is twice as thiok. Tho 
wings are slightly dusky and at their bases arc tinged with tawny yellow. They have tho 
three longitudinal veins whereby the genus Cecidoinyia is characterized, the middle vein 
towards its apex and the forks of tho inner vein being very slender for a species so large ns 
this; and the cross vein between the middle and outer longitudinal veins, which is seen in 
many of the insects of this genus, is wanting in this speoies. The poisers are dusky. The 
legs are pale brown, the thighs paler at their bases, and tho feet are black. The different 
pairs of legs equal each other in length, and are about 0.24 long when extended, of which 
length the feet form one-half. Tho short basal joint of the feet is so indistinct that often it 
is only after an examination of several specimens that one becomes assured such a joint really 
exists in this species. 
In tho HALE the antenna: are threo-fourths the length of the body, with the joints short 
oval and almost globular. Each joint is surrounded with a whirl of longish hairs. Tho ter¬ 
minal joint does not differ from thoso which precede it. The two basal joints are compacted 
together as in the female. The antennm diminish very slightly in thiokness towards their 
tips. The pedicels separating tho joints are smoky, translucent, nearly as long ns tho joints 
and about a third as thiok. The abdomen is cylindrio or slightly tapering towards its tip, 
and is formed of seven joints in addition to tho terminal one, which is transversely oval and 
gives off two robust processes whioh arc armed each with an inourvod hook at its tip. Tho 
abdomen in the living specimen is black or brownish binok, with bands at the sutures both 
above and beneath, of a brick rod, tawny yellow, or grayish color, varying in their width as 
this part of the body is more or Icbs distended. In nil other respects the malo fly corresponds 
with the femule. 
