174 
with a diameter at the posterior end of 1.5 mm . While feeding, if the 
food supply is sufficient, it does not move about much, entire clusters 
of larva? often completing their growth in the same bony crevice in 
which the mother fly had deposited the egg^>. When mature, however. 
it crawls, pulling itself along, apparently by the mouth hooks, into 
some fold of the wrapper that is comparatively dry and from which the 
fly will easily be able to escape. Here it begins to contract in length 
and assume a yellowish hue. and the separation of the outer skin 
from the body can be clearly seen. The former gradually hardens 
and darkens into a golden brown, oblong segmented shell, 4 to 
5 mm in length, and which still retains the larval projections on the 
posterior end. Within this puparium the larva rests for a time, I have 
reasons for believing, for thirty- six or forty-eight hours, perhaps longer, 
unchanged, except for a slight reduction in size. (I had occasion to ob- 
serve the actions of one of these larva? whose case was accidentally 
broken. It wriggled and twisted about in the most unsatisfied manner, 
but seemed to have lost its skipping power, and was constantly thrust- 
ing its head or its posterior extremity into the deserted puparia that 
were scattereolin the bottom of the jar. Whether it was able to com- 
X)lete its transformations I can not now say. | 
Both transformations, although involving such radical, formal and 
functional changes, take place within a period of ten days, as nearly 
as I have been able to ascertain. 
The perfect insect is a shining black fly with bronzy tints on the 
thorax and slight iridescence of the wings. The latter overlap nearly 
to the tips when the insect is at rest. The legs are dull black, shaded 
at the joints to dull yellow or fuscous. In size it is about one-half that 
of the common house fly. There is no good figure of this insect in any 
American publication, that in Packard's Guide being in outline 
merely and not available for recognition except by the skilled ento- 
mologist. The fly is not active at night, but is able to perform its life 
work in the obscurity of partially darkened closets and storerooms. 
To make these absolutely dark would, in my judgment, effectually 
exclude it. 
I have not been able to make it oviposit on fresh meat of any kind, 
nor does it seem able to breed upon that which is simply salted, but not 
smoked, not even when such meat is folded in wrapping papers. It 
will sip a,little at sweets, but is not greatly attracted to them, while 
the odor of smoked meat speedily summons it. The average duration 
of life, in the perfect state, in summer, does not exceed a week, accord- 
ing to observations made upon it in the rearing jar. which may not. 
however, exactly indicate it. The entire life cycle would seem to be 
included within three weeks, but there is no definite succession of 
broods, and the insect may be found in all stages from May until 
October or November. When exposed to severe and protracted cold, 
larva?, pupa?, and flies are killed. The flies speedily succumb to 
