190 NORTH AMERICAN INSECTS. 
their spiny legs in contact with their wings; or with 
crickets, by rubbing their wings together; and with flies 
and the different species of bees, who make a noise by the 
rapid motion of their wings. 
Among many others we have every year attempted to 
raise a number of these handsome caterpillars, but have 
often been unsuccessful in bringing them to their final 
metamorphosis, because, as soon as they were full grown, 
they ceased to take food, became sick, and died. In such 
cases we have noticed the surface of their bodies com- 
pletely covered with small, shining, white silky-looking 
grains, resembling minute seeds, and if one fell off its place 
was immediately supplied by another. These white specks 
were the silky cocoons of diminutive ichneumon-flies, 
whose mothershad stung the poor caterpillar when very 
young, and deposited many hundreds of eggs in as many 
hundred wounds. The larve proceeding from these eggs 
dwell between the skin and the fat of the caterpillar, on 
which they feed, being very careful not to attack any vital 
part of the body. Thus the unfortunate caterpillar is for 
several weeks being slowly devoured, while it continues to 
eat and to grow for the benefit of its tormentors, until all 
its fat is consumed by these parasites, when, having no 
strength or vitality left with which to accomplish its meta- 
morphosis, it lingers along a few days, shrinks to the fourth 
part of its former size, and finally dies in agony. Then 
the small cocoons of the ichneumon-flies fall to the ground, 
and a few days after assume their perfect form, and fly 
about, after the example of their mothers, to seek new 
victims. 
While on the subject of Hawk-moths, we can not omit a 
brief incidental notice of one species, which is a native of 
the southern parts of Europe, because even now it spreads 
a general terror among the ignorant and superstitious. 
And we do this the more willingly, because many Ameri- 
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