348 [Assembly 
viscera. At this end is often observable one or two little brush-like 
granules, resembling those on the soles of the feet of some carabidous 
insects. (One of these is indicated on the anterior edge of fig. i.) 
Are these the relics of the suctorial mouth of the larval This lar¬ 
va case is comparatively tough and leather-like at first, but becomes 
more brittle and also darker with age. 
Characters of the dormant larva. —On carefully opening the larva 
case just described, a worm (fig. k.) is found within it, scarcely dif¬ 
ferent in any respect from what it was immediately before entering 
upon this flax seed state. It has the same oval form, opake milk- 
white color, and green, cloud-like visceral spot or line beneath. 
The nine segments into which it appears divided, however, are now 
much more distinctly marked than they previously were, the trans¬ 
verse lines being more deeply imj ressed, and the margins showing 
corresponding crenatures. No traces of the members of the future 
fly are yet discernable. The insect now undergoes no further 
change, for a period of five months or more. Enveloped in its flax 
seed like mantle, and reposing at the root of the now lifeless grain, 
it is buried beneath the snows of winter. Over one-half of its en¬ 
tire term of life is therefore passed in this state. 
Error in previous accounts. —This is the stage of this insect, 
which has been spoken of by all preceding writers as its pupa or 
crysalis state. Upon a close observation of Cecidomyia tritici, the 
writer succeeded in discovering that that species had, what some 
had conjectured, but none had actually observed, a regular pupa 
form, identical with that of other species of Cecidomyia, whose 
metamorphoses had been fully described. It hence appeared neces¬ 
sary to distinctly mark that long period of inactivity which inter¬ 
venes in the wheat-fly, after the larva has completed its growth, and 
before it enters its pupa state ; it was therefore, during this stale of 
its life denominated a dormant larva, in my essay upon that species. 
It occurred to me whilst writing out that essay, that the dormant 
larva state of the wheat-fly, was exactly analogous to the flax seed 
state of the Hessian fly, and in a note, my suspicions were expressed 
that the real pupa of the Hessian fly had never been detected. The 
ample opportunities which I have since enjoyed for investigating 
