432 Annals Entomological Society of America [Vol. VI, 



the embolium is called the median furrow (m-f). The margin 

 of the clavus, which when the wing is at rest lies along the lateral 

 edge of the mesoscutellum, is called the margo scutellaris (m-s), 

 while the margin of the clavus beyond the tip of the meso- 

 scutellum, is called the commissura (cm). 



There are three angles in the coriaceous portion, used in 

 classification. These are as follows: the internal angle, angulus 

 internus (a-i) formed by the meeting of the sutura membranae 

 and the sutura clavi ; the angulus clavi (a-c) , which lies between 

 the sutura clavi and the commissura ; and the angulus scutellaris 

 (a-s), which is formed by the meeting of the commissura and the 

 margo scutellaris. 



The coriaceous portion of the wing has an inconspicuous 

 venation to which the following names have been given. The 

 costa (ca) is the longest vein, lying nearly parallel to the costal 

 margin of the wing. The subcosta (sea) and radius (ra) lie 

 posterior to the costa, their basal halves being coalesced. Behind 

 or posterior to the coalesced subcosta and radius, lies the median 

 vein (me) connected by a short cross vein (r-m) near its tip 

 with the radial sector. The cubitus (cu) lies within the clavus; 

 and the first anal vein (a) lies along the margo scutellaris except 

 at its base where it extends into the clavus. 



The anterior part ©f the mesopleuron is hidden under the 

 prothorax. It is partially divided into two sclerites, the epime- 

 ron and the episternum, by the coxal cleft over the insertion of 

 the mesocoxa. A third plate which is a marked off portion of 

 the epimeron lies at the base of the fore wing and is wholly 

 hidden by the prothorax. It is called the basalar plate (ba). 

 A chitinous plate called the prealar bridge (o) connects the 

 pleuron and the scutum near the juncture of the mesothorax 

 with the prothorax. Below this plate lies the mesothoracic 

 spiracle (sp) in the intersegmental membrane between the meso 

 and prothorax. Posterior to the basalar plate is an invaginated 

 triangular apodeme (ap) whose position is. indicated externally 

 by a cavity. A continuation of one of the angles of this cavity 

 marks off part of the dorsal border of the pleuron causing it to 

 appear as a sclerite. A membranous area extends from the 

 base of the fore wing to the prealar bridge, and separates the 

 scutum from the pleuron and its plates. 



The sternum is of one piece solidly fused with the episternum. 

 The coxal cavities are formed by the inner surfaces of the 



