152 KANSAS UNIVERSITY SCIENCE BULLETIN. 



sensory hairs, in prominent pits, much more evident, however, 

 in the male than in the female. 



GENITALIA. 



Male Genitalia. — The genital segment of the male of 

 Pachypsylla celtidis-mammse is described by Riley as follows : 

 "Male genital segment a little longer than the preceding ven- 

 tral segment, brown, shining; plate as high as the length of 

 the segment, lateral lobe barely indicated, anterior margin 

 straight, posterior margin very slightly oblique, i. e., the plate 

 gradually increases in width towards the tip, which is truncate 

 and not arctuate, as in the preceding species. Forceps as in 

 venusta [two-thirds as high as plate, front margin straight, 

 hind margin slightly sinuate at basal half, tip rounded, outer 

 face smooth and very shining]." 



The genital segment of the male consists of the following 

 parts: Supra-anal plate or "genital plate," subgenital plate, 

 forceps or "posterior processes," and copulatory organ or 

 "sedeagus." 



The supra-anal plate is a conspicuous fleshy process attached 

 to the anterior edge of the subgenital plate. It is generally 

 carried at about right angles to this plate, and is shown in 

 55-10 as drawn forward out of normal position. It averages 

 about 0.48 mm. in length (measured on cephalic surface) and 

 its greatest width is 0,19 mm. Looking cephalad at this plate 

 it is seen to taper at top and bottom, and to be convex with 

 rather wide flaps on its lateral edges (30-6, sppfi). At its 

 distal end these flaps recede to the edge, where the organ 

 ceases to be an open trough, and becomes a short, rounded, 

 truncate, cone-shaped structure (30-6 and 7, x) , connected 

 by its cephalic wall to the basal wall of the trough below. This 

 structure ends in a short, flaring, membranous ring (figs. 6 

 and 7, a), which is the external opening of the anus. The 

 concave face of the plate is lined with a delicate, folded mem- 

 brane, between which and the cephalic wall is situated a tube, 

 the rectum. Almost the entire surface of the plate carries 

 numerous long, stiff hairs. 



The lower extremity of the supra-anal plate consists of a 

 chitinized ring which expands into a rather broad, two-lobed 

 plate, Ip, on each side. These plates drop ventrad at their inner 

 edges much after the fashion of a funnel, and form the base of 

 the copulatory organ. 



