THE NATURE OF 'METAMORPHOSIS. 67 
skeleton. This is what takes place in lepidopterous insects. 
Some of the Coleoptera , as in the instance of Melolontha vulgaris , 
the common Chaffer Beetle, remain for a greater length of time 
in their nests before they come abroad, after entering the imago 
state. This is also the case with the humble-bees. When 
these insects first come from their cells they are exceedingly 
feeble, their bodies are soft, and covered with moisture, their 
thick coating of hairs has not acquired its proper colour, but 
is of a greyish white, and they are exceedingly susceptible of 
diminished warmth. They crowd everywhere among the cells and 
near other bees, where there is most warmth. In a few hours 
this great susceptibility is diminished, and their bodies acquire 
their proper colours, but they do not become sufficiently strong to 
be capable of great muscular exertion, and undertake the labours 
of the nest, until the following day. When an insect has once 
entered its perfect state, it is believed to undergo no further meta- 
morphosis or change of covering. But there exists an apparent 
exception to this general law in the Ephemeridce , which are noted 
for the shortness of their existence in the imago state. When 
these insects have crept out of the water and rid themselves of the 
pupa covering, and their wings become expanded, they soon take 
flight, but their first movements in the air are performed with some 
difficulty, and they shortly alight again and throw off a very deli- 
cate membrane with which every part of the body has been 
covered, and then resume their flight with increased activity. The 
condition of the insect previous to this final change has been 
called the pseud-imago state.” 
The structural changes which occur during metamorphosis are 
certainly equalled, in the interest they must excite, by the psy- 
chical ; and the habits, instincts, and passions witnessed during 
the different phases of existence are indeed most diverse. 
F 2 
