370 EXTERNAL ANATOMY OF INSECTS. 
*, PsEuponycuta (the Spurious Claws). See definition 
under Pedes Postici. 
ii. Atrrruncus (the Alitrunk). The posterior segment 
of the trunk to which the abdomen is affixed, and 
which bears the legs and wings?. It includes the 
Mesothorar and Medipectus, and the Metathorar 
and Postpectus. 
i. MesorHorax (the Mesothorax). ‘That segment of 
the alitrunk which bears the Elytra, or the anterior 
pair of wings, and the intermediate pair of legs °. 
It includes the Collare, Prophragma, Dorsolum, 
Scutellum, Franum, and Pnystega. : 
A. Cottare (the Collar). The first or anterior piece of 
the Mesothorax. In most insects that have a con- 
spicuous Prothorax, as the Coleoptera, this piece 
appears scarcely to have a representative; but in the 
LIubellulina it co-exists with it, and is more con- 
spicuous*. It is particularly remarkable in Hyme- 
noptera and Diptera. 
B. Propuracma (the Prophragm). <A partition of an 
elastic substance, rather horny, connected posteriorly 
? Prarte VIII. Fic. 3, 4, 12—14, 16, 17. and IX. Fie. 1, 3, 7, 
8, 10—12, 15. > Ibid, ¢. 
© Prate IX. Fic. 7, 11, 12, 15, 19. g’. The Collare of Hymeno- 
ptera and Diptera has usually been regarded as representing the 
Prothorax of Coleoptera, Orthoptera, &c. But this difference obtains 
between them—the latter evidently belongs to the Manitrunk, and 
its muscles do not appertain at all to the Alitrunk ; whereas the Col- 
lare as evidently is a part of the latter, its muscles belong to it, and 
its functions in assisting in flight are important. These reasons, and 
others we shall state hereafter, induced us long ago to consider this 
part as not representing the Prothorax ; and they seem to have in- 
duced M. Chabrier almost to adopt a similar opinion. Sur le Vol des 
Insectes. Ann. du Mus, 3eme Ann. 414. et 4eme Ann, 54—. 
