ORTHOPTERA— F0RFICULAR1.E. 211 



interpreted. The resemblance they show to the female of L. commixtum 

 leads one, however, to believe tliis the correct view. 



The species resembles the preceding, especially in the female speci- 

 mens, biit the forceps of the male differ considerably. 



Florissant. Five specimens, Nos. 2779, 492."), 14688 (s), 8334, 9228 (?). 



6. Labiduromma gilberti. 

 PL 16, Fig. U{S). 



Head small, subtriang-ular, with well-rounded contours. Antennae 

 reaching to tlie tip of the tegniina, apparently fourteen-jointed, the basal joint 

 obscure, the middle joints four times as long as broad, a little larger in the 

 middle than at the ends. Pronotum quadi'ate, scarcely broader than long, 

 distinctly smaller than the head, and scarcely half as broad as the combined 

 tegmina; posterior margin broadly rounded. Wing-veins with more widely- 

 spread forks before the median break than in L. exsulatum. Legs short, 

 the middle pair midway between the others and a little smaller than the 

 hind pair, the femora broad and flattened, twice as broad as their corre- 

 sponding tibiae. Body moderately broad, with straight parallel sides ; the 

 last segment three-quarters as broad apically as basall}', the apical margin 

 nearly straight, the sides well rounded. Pygidium minute, triangular. 

 Forceps large and long, the basal two-fifths broad, equal, straight, simple, 

 attingent, beyond falciform, much smaller, tapering to the middle of this 

 portion, bej'ond it equal, the tip bluntly rounded and a little contracted (<?); 

 comparatively slender, straight, parallel-sided at the extreme base, beyond 

 tapering regularly by excision of the inner margin, the tip slightly incurved 

 and bluntly terminated (?). 



Length of body excluding forceps, c? 15.5"""; breadth of head, 2.3°"; 

 of pronotum, 1.5"""; of combined tegmina, 4.5™"; of abdomen, 3.8""; 

 length of forceps, S 4.5"", 2 3.25""; breadth at base, S 1.25"", ? 0.8"". 



The species has a more modern look than any of the others, and in 

 none are the forceps more falciform, reminding one to some degree of For- 

 ficula auricularia. It is named for Mr. G. K. Gilbert, of the U. S. Geolog- 

 ical Survey. 



Florissant. Three specimens, Nos. 4736, 7352 {^), 8782 (?). 



