1916] Thoracic and Cervical Sclerites of Insects 53 



and those behind the postparapterum or epimeral paraptera. 

 Snodgrass claims in his "Anatomy of the Honey Bee," pp. 20, 

 footnote (a), that Audouin, '24, termed these plates the parap- 

 tera and hence Snodgrass would retain this term. This, 

 however, is not the case. Audouin, '24, termed the small 

 sclerite which sometimes extends along the anterior edge of the 

 episternum the "paraptere" and confuses it with the tegulae 

 and other sclerites at the base of the wing. Later Audouin, '32, 

 clearly defined the "paraptere" as the tegulae (1832 Audouin, 

 Exposition de L'anatomie du Thorax, par W. S. MacLeay, 

 Accompagnee de notes par M. Audouin. Ann. Sci. Nat. 

 XXV, Ser. 1, pp. 41, footnote.) He says: "In fact I consider 

 as the paraptere the small piece so visible in the Hymenoptera 

 and in the Lepidoptera, which covers the base of the fore wings 

 and which has been designated by the name ecaille, epaulette or 

 squamala. " Jordan, '02, terms the subalar plate the "para- 

 sternum" and also applies this term to the anepisternum 

 (upper portion of the episternum) in his figures. His homologies 

 of the sclerites are evidently incorrect. Berlese, '06, termed the 

 basalar sclerites the "acrosterno o prefulcro (anteriore e 

 posteriore). " The subalar sclerite he terms the "paraptero, " 

 (Gli Insetti, pp. 244). "Prefulcro" is a good term for the 

 basalar sclerites, as it designates their position in front of the 

 wing fulcrum, but the term "paraptero" does not seem desir- 

 able. Crampton's, '14, term, subalar sclerites, is far more 

 suitable since it exactly describes the position of these sclerites. 



The pleuron may be more or less modified in different 

 insects. In the mesothorax of some Diptera, the parts have 

 shifted forward, thereby causing the pleural suture to become 

 twisted and curved (Fig. 11, pls2). In Odonata the pleuron 

 assumes an oblique position and as a result, the episternum 

 becomes dorsal and the epimeron ventral. In other insects the 

 pleural sclerites are variously modified in shape and size. 



Crampton, '08, was the first to suggest that the pleuron 

 probably consisted originally of but one plate and that the 

 episternum and epimeron may have been formed by the infolding 

 of the integument, due to muscle stress. This view was later 

 developed by Snodgrass, '09. In such insects as Eosentomon, 

 Leuctra (prothorax), acridid nymphs and Anisolabis, the pleuron 

 is apparently represented by a single plate, in which the pleural 

 suture is present. If the pleuron was originally a single plate, 



