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above and beneath, of a brick red, tawny yellow, or grayish color, 
varying m their width as this part of the body is more or less dis¬ 
tended” (Fitch). The claspers at the end of the body are stout, 
much more so than in Cecidomyia leguminicola of the clover. 
The egg (Plate I, a, enlarged) is very minute, about a fiftieth of 
an inch iong, cylindrical, pointed at each end, the shell shining and 
transoarent, the egg being of a pale red color. 
The larva.— After remaining. about four days in the egg state, the 
larva or maggot of the Hessian Fly hatches, and is of the form 
represented by plate I, fig. b, and plate II, fig. B, Bu, B b, Be. 
The body is soft, smooth, shining, oval cylindrical, beneath a little 
flattened, and consists of twelve segments besides the head, the lat¬ 
ter soft, fleshy, and but slightly separated from the body, with very 
rudimentary mouth-parts (jaws, etc.). The rings or segments are 
moderately convex and tolerably distinct from one another; the 
sutures between the segments in the living larva being indicated by 
faint transverse lines of a greenish brown hue, according to Fitch, 
who also states that the mature worm, freshly taken from the roots 
of the wheat, measures about 0.15 of an inchin length by 0.06 inch 
in width. Mr. Biley informs us that there are nine pairs of minute 
spiracles, which appear as yellowish rounded tubercles. 
The puvarium or flaxseed state (Plate I, Fig. c, Plate II, Fig. D).— 
When fully grown the larva is ready to transform into the third or 
pupa stage of its transformations. The body turns brown, and finally 
of a bright chestnut color, while the skin loses all appearance of 
sutures, and assumes a rude spindle-shaped form, somewhat larger 
than the larva. This brown case protects the growing pupa within 
the skin of the latter, finally separating from the cast larva skin, 
called the pupa-case or puparium, and which serves as a sort of 
cocoon to protect the pale, soft-bodied pupa within.. While many 
two-winged gall-flies are protected by the galls within which they 
live, others, like the larval wheat and clover-seed midge and the 
pitch-pine midge, spin true cocoons of silk; and the Hessian-fly is 
the only species of the genus or family 7 , so far as we know, which 
assumes this puparium state, being peculiar to the house fly and 
other species of Muscidse and allied families, in which the pupa is 
said to be coarctate, i. e., protected by the cast dried brown skin of 
the maggot or larva. 
From the decided resemblance to a flaxseed, the insect, when at 
this stage of its transformation, is said to be in the “flaxseed state. 
It is, however, rather flatter than a flaxseed, being pinched, as it 
were, at the head end of the body. I have taken the semi-pupa or 
incompletely-formed pupa from the flaxseed December 1. In this 
flaxseed state the partly-formed pupa resides during the five winter 
months of the year. . _ . 
In early spring, during warm weather in April, the semi-pupa 
rapidly transforms into the complete pupal or chrysalis state. 
The pupa (Plate II, C).—As we have not personally observed the 
mode in which the fly issues from the pupa and its case, we extract 
the following account from Fitch. By the time the insect reaches 
the pupa state the flaxseed case has become quite brittle, breaking 
asunder transversely if rudely handled, one of its ends slipping off 
from the insect within, like a thimble from the end of the finger: 
