to some of the Insect Tribe. 51 
to illustrate the extraordinary instincts peculiar to some of 
the insect tribes, and also afford an interesting subject to 
the practical entomologist. 
My present communication is to give you a brief detail of 
observations regarding the repr oduction, or rather the propa- 
gation, of a very small species of ichneumon fly (Zchnetmon 
ovuldrum of Linn., P latygdster ovulorum of the fam. Procto- 
trupide of Latreille). 
On the 28th of last month (June) I put twenty caterpillars 
of the large cabbage butterfly (Pontia br Assicee) into a wire 
cage: they were mostly full-sized lary vee, and continued to feed 
on cabbage leaves placed i in the cage with them. On the fol- 
lowing day, June 29., five or six of the largest left the leaves, 
and cr rawled about on the sides of the cage duri ing the rest of the 
day. The next morning, June 30., I found them resting on large 
clusters of minute cocoons of an ovate form (fg. ‘9. 2), the 
largest not exceeding two lines in length, and about the thick- 
ness ofa caraway seed. Each was enveloped with a fine yellow 
silk, resembling that of the common silkworm (the pupa of Pha- 
Jeena mori). On these clusters the caterpillars remained the 
whole day without moving. Fresh leaves were given to the 
rest ; but in the course of this day they all left oft feeding, 
crawled about the cage, but underwent no other change. 
ialy the next day, July 1., I found they had, with the exception 
of two or three, all ejected the pare asitical progeny they had been 
impregnated with, and, like the preceding cater pillars, continued 
resting on the ee they had formed: the remaining three 
followed the example of the others, and the last oper ation of 
these devoted caterpillars was to envelope each cluster in a 
veil, formed of the most delicate web. Some of them executed 
the task; but the greater part were too feeble to complete it; 
and in the course of three days more, July 4., they became 
motionless, and gradually, one after another, fell, shrivelled 
and exhausted, to the bottom of the cage. 
The clusters of cocoons varied in their numbers; some con- 
tained upwards of a hundred, others not more ha sixty or 
seventy. I watched during ae day to witness the change from 
the larva to the pupa state, but in vain; the operation was 
performed during the night, and it was only in the last two or 
three caterpillars, i in an enfeebled state, that I observed the 
larvee of the ichneumon fly emerging from the lower side of 
the caterpillar ; but the few which came forth remained in- 
active during the rest of the day. 
On July 12., the first-formed clusters of cocoons evinced a 
state of maturity, and in the course of the day numbers of 
the perfect insects came forth. Their exclusion was effected by 
E 2 
