1916] Thoracic and Cervical Sclerites of I?isects 67 



projects free is also divided longitudinally by a suture into an 

 anterior and posterior region (Fig. 10, tnl). It articulates 

 with the coxa and has an inward projecting process at its 

 extremity. These features are also present in the trochantin 

 of Periplaneta. 



The trochantin of the pro- and metathorax in Forficida, 

 assumes the shape of a triangle (Fig. 8, tni, tns). This sclerite 

 may be the entire trochantin or it may be the fusion product 

 of the trochantin and part of some other sclerite such as the 

 precoxale or antecoxale. In the mesothorax there are three 

 small sclerites between the trochantin and the coxa, one of 

 which is probably a detached portion of the coxa and the others 

 of the trochantin (Fig. 8, tn2). 



Sharp, '95, in discussing the thorax of insects (Camb. 

 Nat. Hist. vol. V, pp. 222) figures the base of the front leg and 

 part of the prothorax of Blabera gigantea. He finds the homo- 

 logies of the thoracic sclerites difficult to determine and his 

 figure is wrongly labeled. The region marked "epimeron" is 

 a part of the trochantin; the "fold of the pronotun" is the 

 epimeron and the sclerite he has termed the trochantin is only 

 a part of the trochantin, viz., the trochantinelle. 



Packard, '98, terms the meron the "trochantin." Jordan, 

 '02, terms a small sclerite lying along the anterior margin 

 of the coxa, the "trochantin. " Comstock, '02, termed the post- 

 trochantin the "trochantin;" the ante-trochantin, the "first 

 antecoxal piece," and the antecoxale, the "second antecoxal 

 piece." Berlese, '00, terms the trochantin the "subcoxa. " 

 Snodgrass, '09, Verhoeff, '02-'04, and others have termed the 

 trochantinelle, the entire trochantin. Crampton, '09, used the 

 term, " trochantinus minor," to designate the trochantinelle 

 and the terms "coxal trochantin" and "antecoxal trochantin" 

 to designate the post- and ante-trochantin. 



Coxa, The coxa is the basal segment of the leg and the 

 only one, which it will be necessary to consider in this paper. 

 It varies greatly in size and shape in different insects, but is 

 always constant in position and serves as a landmark in homol- 

 ogizing the thoracic sclerites. In some forms it is undivided 

 and in others it is composed of two or more pieces (Fig. 8, cxs). 

 It articulates with the coxal process and with the trochantin 

 when the latter is present. 



