OKTHOPTERA FOKF1UULAKLE. 205 



One of the species here described, certainly distinct from the others, is 

 so imperfectly preserved that no name is given to it. The others may be 

 distinguished by the following' table: 



2'able of the specie* of Labiduromma. 



Species of largo size with very long forceps (the total length nearly or quite iJo mm ). 



Male forceps almost one-half a.s long as body 1. L. aria. 



Malt: forceps scarcely more than one third the length of body ',>. /,. bormanri. 



Species of smaller si/.o and shorter forceps (only a little exceeding iiO" ml ). 



Hind margin of last abdominal segment of male strongly angnlated ; no pygidinm perceptible. 



H. L. mortalf. 



Hind margin of last abdominal segment of male straight or nearly straight ; pygidinm distinct and 

 sometimes largo. 



Male forceps with large projecting interior tooth at base 4. L. commiitum. 



Male forceps with no projecting basal tooth. 



Male forceps narrowing almost from base 5. L. tertiarium. 



Male forceps with equal parallel sides for some distance from base. 



Male forceps comparatively slender, with distinct and tolerably strong falcation. 



C. L. gilberti, 



Male forceps broad beyond the base, with weak falcation 7. L. etsulalum. 



Species of much smaller size and generally still shorter forceps (the total length about 15 mm or less). 



Male forceps stout at base, much smaller and equal beyond ?. L. lithophitum. 



Male forceps slender and delicate throughout. 



Male forceps less than half as long as abdomen 10. L. infernum. 



Male forceps fully half as long as abdomen II. L. labent. 



1. LABIDUROMMA AVIA. 

 PI. 16, Figs. 5, 22 ( $ ), 3, 11, 23 ( 9 ). 



Head small, rounded triangular ; antennae in no case well preserved, 

 the longest fragments scarcely reaching the tip of the tegmina, the basal 

 joint not precisely determinable, but apparently about twice the diameter 

 of the stalk and subglobulur : the proximal joints of the stalk are cylindrical 

 and from two to three times as long as broad, so that if composed as usual 

 in this genus the antennae could not have extended beyond the tip of the 

 tegmina; palpi shorter than the diameter of the head, nearly as stout as the 

 antennas, the joints half as long again as broad. Pronotum nearly circular 

 but subquadrate, apparently longer than broad, and narrower than the head 

 in the female (where it is better preserved than in the male specimens) and 

 the opposite apparently in the male, where it seems to equal or surp'ass the 

 head in breadth. Tegmina together considerably broader than the head, 

 and square, of equal length and breadth; folded wings protruding beyond 

 the tegmina to a distance of three-fourths the length of the latter. Legs 



derately stout and not very short, the second joint of the tarsi apparently 



cordate. Abdomen equal with parallel sides. Forceps simple but of great 



