154 PROCEEDINGS OF THE ACADEMY OF [May, 



and generally regular, transverse sectors; anal sulcus impressed, 

 moderately, strongly arcuate distad, jointing the sutural margin 

 faintly distad of the proximal third; axillary veins and their numer- 

 ous intercalated accessories regularly placed. Wings reaching 

 almost to the apex of the abdomen, broad, their greatest width 

 contained almost t^\'ice in their greatest length; costal margin 

 largely straight oblique proximad, gently arcuate distad, the apex 

 well rounded rectangulate and entirely in the anterior field; periph- 

 eral margin of the posterior field regularly arcuate, except for the 

 frequent, short, bulging arcuation at the apex of the axillary vein 

 and rami; intercalated triangle very small; mediastine vein largely 

 straight oblique; discoidal vein straight proximad, weakly arcuate 

 distad; costal veins (including the more distinct ones arising from 

 the mediastine vein) twenty-one in number, oblique, non-clavate; 

 medio-chscoidal area distinctly narrower than the medio-ulnar area, 

 appreciably narrowing distad, with the transverse rami rather 

 regularly placed, twenty in number, the majority weakly bent 

 arcuate, the areolets generally subquadrate; median vein simple, 

 of much the same curve as the cUscoidal vein; medio-ulnar area 

 with the transverse rami less numerous than those of the medio- 

 discoidal area, fifteen in number, incomplete costad, the areolets 

 more rhomboid than quadrate: ulnar vein with two complete and 

 seven incomplete rami; axillary vein with two rami cUverging 

 slightly proximad of the middle. Abdomen with the disto-dorsal 

 segments having the structure usual in Ischnoptera: supra-anal 

 plate in general subquadrate, very faintly transverse; distal margin 

 bisarcuate laterad of a shallow, median, arcuate emargination, the 

 whole margin, but particularly these arcuate portions, supplied 

 with long bristle-like hairs; surface of disto-dorsal section of the 

 plate with two areas of impression:" cerci elongate, styliform, 

 acuminate, depressed dorsad, rounded ventrad, strongly hirsute: 

 subgenital plate asymmetrical; free margin sinistrad with an arcuate 

 emargination, in which is placed the sinistral style, mesad with a 

 transverse, truncate section, in the dextral angle of which is situated 

 the dextral style, dextrad of this is a deep acute-angulate emargina- 

 tion, in which is visible an acute, lamellate projection of the internal 

 genitalia, dextrad of this emargination and mesad of the cercus 

 the margin develops an erect, lamellate peg-like process, which 

 projects dorsad of the supra-anal plate when the parts are in their 

 normal position, the apex of this process is covered with erect, 



" The presence of these areas may not be a normal condition. 



