76 EYE SPY 
developed, to say nothing of their wiggling pro- 
pensities. 
How well I remember the. " whack ! whack ! 
whack !" from the inside of the pasteboard or 
wooden box as I entered the room, or chanced to 
make the slightest commotion in its neighbor- 
hood, as the captive pets threatened to dash their 
brains out in their demonstrations at my approach. 
Opening the box, I was always greeted with the 
same concert of whisking heads, the action being 
more particularly expressive from the long pro- 
jecting lash of hairs, an inch and a quarter in 
length, with which the caterpillar's head was pro- 
vided. One singular feature of these hairs had 
always puzzled me in the earlier life of the cater- 
pillar, but was soon explained by close observa- 
tion. At intervals of every quarter of an inch or so 
in the length of the slender tuft we find, in perfect 
specimens, a tiny brown speck perhaps three or 
four graduating in size to the tip of the hairs, 
where the atom is scarcely visible, or generally 
absent. A careful examination of their shape re- 
vealed the fact that they were exactly like the 
heads of the younger caterpillars in all their 
stages, and their presence and successive accu- 
mulation were readily explained by the moult- 
ing habits of the caterpillar, which is common 
to all caterpillars. By these telltale tokens we 
know that the professor has changed his clothes 
