42 
LETTERS ON ENTOMOLOGY. 
a kind of passive defence in long stiff hairs, 
which quickly breaking and piercing the flesh, 
create great inflammation, and smart like the 
sting of the nettle. Lesser having touched the 
horn of a sphinx caterpillar, it suddenly turned 
round its head, and ejected from its mouth a green, 
viscous, and very foetid fluid, which, though he 
repeatedly washed his hand with soap and fumed 
it with sulphur, infected it for two days. The 
caterpillars, also, of a particular tribe of saw- 
flies, when disturbed, eject a drop of fluid from 
themouui. x^. — . i .,, „.». ,. 
has the peculiar power of making a sound like 
the squeaking of a mouse, which is certainly the 
best defence it could have, as few people would 
like to touch a squeaking caterpillar. There is a 
small brown species which exactly resembles a 
dried stick, and holds itself erect like a little 
branch ; it is astonishing to see how long it will 
hold itself in this position, which, though it ap- 
pears painful to us, may be the very reverse to 
the insect. 
The maggot of the cheese, which turns to a 
black shining fly, takes amazing leaps : Swam- 
merdam saw one, only a quarter of an inch long, 
jump in this manner from a box six inches in 
depth ; which is in the same proportion of height 
