8 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. $6 



consists of two lobular parts, of which only the ventral one (the 

 anterior praescutum of Lowne) extends right down to the root of 

 the wing. The boundary between the two processes is formed by 

 the cleft that runs along the crista spinalis. The ventral portion 

 of the processus praealaris passes below into a narrow ligamentous 

 band that thins out distally, and is attached to the inner side of the 

 processus pteralis alae 2 (the coracoid of Lowne, pi. 8, fig. 23, pt2). 

 The processus praealaris and postalaris are connected with each other 

 by a narrow, chitinous bridge which is very tender and easily de- 

 stroyed in preparing the specimens (pi. 8, fig. 23 ; in all the other 

 illustrations it is lost). The processus postalaris is a chitinous strip 

 which decreases in size opposite the root of the wing, and has at 

 its end a somewhat deep depression, the sella processus postalaris. 

 In this lies, at an angle of 90 degrees, the proximal notch of the 

 pterale A (pi. 8, fig. 24; pi. 9, fig. 25, ptA). Lowne calls the 

 processus prsealaris the parascutum. I have found no evidence that 

 it should be considered as a separate piece. At the point of separa- 

 tion of the ventral and dorsal portions of the processus praealaris a 

 small finger-shaped process, the processus dactyloformis (pi. 2, figs. 

 3, 4, pd), is situated. This extends dorsally into the interior of the 

 thorax. 



The scutellum (pi. i, fig. i ; pi. 2, figs. 3, 4, se) has, when looked 

 at from above, the shape of an equilateral triangle. The sides of 

 this triangle are convex, and one of its corners is anal. The anal 

 portion overhangs. The scutellum is beset with bristles along its 

 edge and also bears two bristles on its back. The scutum is con- 

 nected with the scutellum by the two scutellar bridges (Lowne). 

 Along the processus postalaris extends a cleft which widens toward 

 the root of the wing to fonn the foramen postalare (the supratym- 

 panic fissure of Lowne; pi. 2, fig. 3, 0^). 



The postscutellum (pi. 2, fig. 3, ps) is cushion-shaped; upon it 

 the scutellum rests. Toward either side it narrows considerably. 

 I doubt whether the postscutellum belongs to the mesothorax, but, 

 since there is not sufficient evidence in favor of any other view, I, 

 for the present, accept this conception. 



The Mesopleura 



Each mesopleurum is made up of the parapleurum, episternum, 

 parepisternum, epimerum and parepimerum. 



The parapleurum (lateral plate of Lowne; pi. 2, figs. 3, 4, pp) is 

 nearly quadrilateral. It is separated from the praescutum by the 



