lOO TRANS. ST. LOUIS ACAD. SCIENCE. 



row but as long as the claws. Wings with a large pentagonal 

 areolet, sometimes incomplete by its terminal vein being subobso- 

 lete. When the areolet is complete the bulla; A and B cover 

 nearly the whole of its terminal side and are separated only by a 

 minute dot, C and D are confluent or separated from each other 

 only by an indistinct dot, and E is as close as possible to the angle 

 of the ist recurrent vein. When the areolet is incomplete A and 

 B are absent, the other bullae remaining the same ; and there are 

 then consequently but 2 bullas, CD and E, instead of 4, A, B, 

 CD, and E. 



Distinct from Exochus and Polyrhabdus by its huuched scutel, 

 by its long, toothed tarsal claws, and its large pentagonal areolet ; 

 and from Alomya by its sessile abdomen, its wings as long as usu- 

 al, and with the terminal veins distinct, its toothed claws, etc. 



[Mr Walsh considered the two following species as belonging to a new 

 genus which he called Pachyonyx ; but they cannot be generically separated 

 from Orthoccntrus, Grav. — Cresson.] 



LOrthOCentrus] trifasciatUS, n. pp.— d'^.— Black. iyea</subopaque with 

 very minute, rather close-set, punctures, more sparse on the subpolished 

 vertex. Face, checks, and the whole mouth, white. Antennae § as long 

 as the body cf, | as long $, with the first joint of the flagellum about 2J 

 times as long as wide, and the following joints about twice as long as 

 wide, brown-black, the scape and the extreme base of the flagellum whitish 

 beneath, especially in c?. Thorax polished, with very minute, rather 

 dense punctures, more sparse on the mesothoracic pleura. Metathorax 

 transversely rugose above, with 4 longitudinal subequidistant carinse all 

 attaining the lunate area of the posterior declivity, which is bounded by 

 a well-defined carina throughout. Lower face of the mesosternum rufous, 

 and in (^ its pleura also fully half way to the wing. Abdomen opaque, 

 very finely and rather densely rugose, subpolished towards its tip and at 

 the tips of the joints. Joint i in d" full twice as long as wide, in $ | 

 longer than wide, d'$ I wider behind than before, c? with its sides nearly 

 straight, $ with its sides strongly convex for the ist J, thence gently con- 

 ■cave nearly to the tip, so that the whole joint is elongate-campanulate, 

 <?$ geniculate at i the way to its tip, which is bisinuate, its 2 cannse 

 -distinct nearly to its tip and enclosing in their basal \ a round excavation. 

 Joint 2 in cf longer by \ than wide, S% with a large, impressed, lateral, 

 «ub-basal puncture, joint 3 square in d*, joint 2 square in $, the rest in 

 d'$ gradually shorter. Joints 2 and 3 with their terminal \ clay-yellow, 

 and joint 1 with a similar band, which in $ is narrower, darker and less 

 obvious. Venter (?$ yellowish except at tip. Four front legs d^ yellow- 

 ish-white ; hind legs very pale rufous, cf with the coxae brown above and 

 the entire femora, or sometimes only their upper surface, and sometimes 

 the tip of the tibiae, brown. Wings subhyaline; veins brown; stigma 



