NIGGER. 
103 
fleshy, without any horny suhstance, and quite without 
sharp points. These legs are used when the grub is 
crawling ; but while he is eating, and the tail, indeed the 
greater pai't of the body, is, as I have already said, cocked 
up in the air, they are quite unemployed. Sometimes, and 
especially when oflended or in danger, the nigger-grub 
coils himself up in a ring, holding the leaf very slightly by 
the first pair of legs, that pair next the head, and when 
touched in this state falls directly to the ground, and there 
lies as though dead ; indeed, if not in a ring before, he al- 
most always rolls himself into one when touched. When 
the nigger has reached his full size, a period depending 
on the temperature of the weather and the supply of food, 
but averaging at twenty days, he burrows in the earth, 
and there makes a little oval house, just big enough for 
his body, which has all at once become shorter and 
thicker : he then plasters the walls of this place with a 
sort of sticky varnish or glue, which he discharges at this 
time only : he keeps on discharging and spreading this 
glue till he is quite surrounded with a strong, tough, and 
hard cocoon, the particles of earth being mixed with the 
glue, and the whole forming an admirable and perfect de- 
fence against wet or the attacks of insects. The period of 
his stay in this cocoon varies according to circumstances ; 
if the weather is hot, it sometimes happens that the grub 
becomes a mummy-like chrysalis in ten days, and a per- 
fect fly and again on the wing in five more; but the 
greater part of the brood remain unchanged all through 
the autumn, winter and spring. I have turned up the co- 
coons, and found the grub little altered even in May. 
Soon after this the change to a chrysalis must take place, 
and the change to a fly occurs, in average seasons^ about 
