BUGS. 193 



beaks. Although the domestic kinds above mentioned are 

 without wing-covers and wings, yet most bugs have both, 

 and, with the former, belong to an order called Hemiptera, 

 literally half-wings, on account of the peculiar construction 

 of their wine-covers, the hinder half of which is thin and 

 filmy like the wings, while the fore part is thick and opaque. 

 There are, however, other insects provided with the same 

 kind of beak, but having the wing-covers sometimes entirely 

 transparent, and sometimes more or less opaque, and these, 

 by most entomologists, are also classed among Hemipte- 

 rous insects, because they come much nearer to them than 

 to any other insects, in structure and habits. Bugs, like 

 other insects, undergo three changes, but they retain nearly 

 the same form in all their stages ; for the only transformation 

 to which they are subject, from the young to the adult state, 

 is occasioned by the gradual development of their wing-covers 

 and wings, and the growth of their bodies, which make it 

 necessary for them repeatedly to throw off their skins, to 

 allow of their increase in size. Young, half-grown, and 

 mature, all live in the same way, and all are equally active. 

 The young come forth from the egg without wing-covers 

 and wings,' which begin to appear in the form of little scales 

 on the top of their backs as they grow older, and increase 

 in size with each successive moulting of the skin, till they 

 are fully developed in the full-grown insect. 



The Hemiptera are divided into two groups, distinguished 

 by the following characters. 



1. Bugs, or True Hemiptera, QHemiptera heteroptera,') in 

 which the wing-covers are thick and opaque at the base, but 

 thin and more or less transparent and wing-like at the tips, 

 are laid horizontally on the top of the back, and cross each 

 other obliquely at the end, so that the thin part of one wing- 

 cover overlaps the same part of the other ; the wings are also 

 horizontal, and are not plaited ; the head is more or less hori- 

 zontal, and the beak issues from the fore part of it, and is 

 abruptly bent backwards beneath the under side of the head 

 25 



