THE CORSELET. 29 



the first, the fore back plate; the second, the mid 

 back plate ; and the third, the hind back plate (*). 



The back of the whole corselet in a wasp (Polistes Billardieri). 

 a, the fore back plate ; b, c, the mid back plates ; c, the mid 

 back scale ; e, g, the hind back plate j e, the first piece ; /, the 

 second piece ; g, the hind back scale ; d, d, the sides of the 

 mid back plate ; h, the fourth piece of the hind back plate j t, t, 

 the under flanks ; k, k, the wing scales of the second pair; /, /, 

 the wing scales of the first pair ; m, m, haunches of the hind 

 legs ; n, part of the abdomen; o, o, p, p t g, q, the sockets of the 

 two pair of wings ; r, r, the spiracles for breathing; s, the cord 

 for the pulley. 



Each of these, in many instances, is composed of 

 four pieces. The fore back plate is thus found to 

 consist of four pieces in locusts and crickets, being 

 in these insects large, and the breast small, according 

 to the law of proportion. In beetles, and most winged 

 insects, however, only two pieces can be readily dis- 



(1) In Latin Tergum prothoracis, Tergum -mesothoracis, and 

 Tergum metathoracis. 



