230 PKOCEEDINGS OF THE ACADEMY OF [PaRT II 



terocular space wide, slightly narrower than that between the 

 antennal sockets. Ocellar spots distinct. Maxillary palpi elong- 

 ate, fourth joint four-fifths as long as third, fifth very shghtly shorter 

 than fourth. Pronotum with surface very weakly convex, greatest 

 width slightly caudad of mesal point. Tegmina very delicate, 

 with (9) longitudinal discoidal sectors, veins with scattered dark 

 dots, representing the bases of microscopic hairs; cross-veinlets 

 moderately developed, moderately darkened in distal portions. 

 Wings with costal veins heavily clubbed distad, ulnar vein with 

 (3) complete branches, intercalated triangle small. Abdomen with 

 dorsal surface unspecialized. Supra-anal plate weakly triangularly 

 produced, about one-third as long as proximal width with apex 

 broadly rounded. Concealed genitalia including a process ter- 

 minating in a broad whorl, its surface covered with very closely 

 placed, minute spines.^'* Subgenital plate convex and curled dorsad 

 on each side, but broadly and shallowly concave in large median 

 portion, distal margin approximately transverse, on each side pro- 

 duced in short, very broad, styles which fuse with the plate at their 

 bases; between these the plate is produced mesad a nearly equal 

 distance, the sides of this portion slanting upward and the free mar- 

 gins concave oblique to the apex; due to the contour of this pro- 

 duction, its apex appears truncate in ventral aspect, but V-emargin- 

 ate in caudal aspect. Each of the styles is nearly twice as broad as 

 its greatest length, the greatest length being on the internal margin, 

 the roundly truncate, broad apex being in consequence oblique 

 to the caudal margin of the subgenital plate. The apices of these 

 styles are moderately thickly supplied with minute but stout spines, 

 directed caudad and curving ventrad. Limbs, their armament, 

 pulvilli,arolia and tarsal claws as characteristic of the genus. The 

 first three of the five or six microscopic teeth on the margin of the 

 flange of the tarsal claws are relatively decided. 



Allotype: 9 ; same date as type. [Acad. Nat. Sci. Phila.] 



Agrees closely with male in size and development of organs of 

 flight, differing as follows. Supra-anal plate with free margin more 

 convex and i-oundly notched at the apex. Subgenital plate short, 

 scoop-shaped, bearing on each side just within the cerci a small 

 lamellate projection, with truncate apex armed with (5 to 7 in the 

 series) closely placed, chitinous spines, resembling the teeth of a 

 comb; within at the base of this process is another projection*" the 



^* The concealed genitalia in the species of this group appear to be very delicate. 

 In the great majority of specimens before us these parts are mashed, and in none 

 do they appear to have dried in a normal position. 



■** The series shows that these processes are variable in contour, as well as 

 occasionally having more teeth and in themselves a very weak character to sep- 

 arate this sex of platystylala from the very similar females of conspersa. An 

 average lesser number of teeth on the inner processes of females of platystylata 

 from Pard, has appeared to us to be a guide to distinguish them from females of 

 conspersa from that locality. It is evident that females of the species of the pre- 

 sent Group will be found as difficult to separate as those of the Impar Group of 

 the genus; determination of female material, without males from the same local- 

 ity, being often out of the question. 



