HEMIPTERA. 219 



different magnitudes, some much larger than the others, and 

 they then prepare for a change that is about to ensue in their 

 mode of life, by emitting from the under side of their bodies 

 numerous little white downy threads, which are^'fastened, in a 

 radiated manner, around their bodies to the bark, and serve to 

 confine them securely in their places. After becoming thus 

 fixed they remain apparently inanimate; but. under these life- 

 less scales the transformation of the insect is conducted; with 

 this remarkable difference, that in a few days the large ones 

 contrive to break up and throw off, in four or five flakes, their 

 outer scaly coats, and reappear in a very similar form to that 

 which they before had ; the smaller ones, on the contrary, con- 

 tinue under their outer skins, which serve instead of cocoons, 

 and from which they seem to shrink and detach themselves, 

 and then become perfect pupae, the rudiments of wings, an- 

 tennee, feet, &:c., being discoverable on raising the shells. If 

 we follow the progress of these small lice, which are to produce 

 the males, we shall see, in process of time, a pair of threads 

 and the tips of the wings protruding beneath the shell at its 

 lower elevated part, and through this little fissure the perfect 

 insect at length backs out. After the larger lice have become 

 fixed and have thrown off their outer coats, they enter upon 

 the pupa or chrysalis state, which continues for a longer or 

 shorter period according to the species. But when they have 

 become mature, they do not leave the skins or shells covering 

 their bodies, which continue flexible for a time. These larger 

 insects are the females, and are destined to remain immovable, 

 and never change their place after they have once become 

 stationary. The male is exceedingly small in comparison to 

 the female, and is provided with only two wings, which are 

 usually very large, and lie flatly on the top of the body. After 

 the insects have paired, the body of the female increases in 

 size, or becomes quite convex, for a time, and ever afterwards 

 remains without alteration; but serves to shelter the eggs 

 which are to give birth to her future offspring. These eggs, 

 when matured, pass under the body of the mother, and the 

 latter by degrees shrinks more and more till nothing is left but 

 the dry outer convex skin, and the insect perishes on the spot. 



