272 THE AMERICAN NATURALIST. [VoL. XXXIV. 
termed by him “ epitrochlea”’! as “certainly the trochantin of 
Audouin," ignoring his previous suggestion that one should 
adhere to the rule of priority. Several other writers, notably 
Latzel (Chilopoda), Comstock and Kellogg (Lepidoptera), and 
Kolbe (Lepidoptera, Trichoptera, and Panorpa), have mentioned 
the existence of an apparent suture in the coxa of certain 
groups under consideration, but without attempting to discuss ` 
its meaning. 
Immediately in front of the metathoracic coxa, particularly 
among the Coleoptera, a small sclerite is discernible, which 
bears the name of ante- 
coxal piece. .This is also 
well shown in Cicada, 
some species of which 
(Cicada dorsata) possess 
a piece homologous with 
that found in the Cole- 
optera ; while in others 
(Cicada tibicen)? instead 
of being chitinized, the 
part is often membrana- 
d^ ceous in structure, and 
serves to retain the coxa 
X12 more firmly in the coxal 
Fic. 5.— Scutigera sp. Coxa An fusion of coxa Cavities, thus indicating 
petto ei iaa its origin ; and the pres- 
ence of a homologous piece in the mesothorax of many 
Coleoptera (Passalus, etc.), occurring at the same time with the 
trochantin, proves that it is distinct from the latter. 
The origin of the three pieces, coxa genuina, meron, and 
trochantin, the relative positions of which are shown in the 
accompanying figures, is more difficult of explanation. A 
 Striking characteristic of the Hexapoda and Chilopoda is the 
more or less complete fusion of the first two (coxa genuina and 
1 The homology of this with the trochantin appears doubtful. 
2 Although a good series was examined in which the other sclerites were well 
chitinized, the absence of chitinization in the antecoxal piece may be the result of 
immaturity. This, however, would not alter the conclusion. 
