Casey — A Revision of the American Paederini. 45 
arcuate, the base a little narrower than the apex; elytra rather less 
elongate, distinctly wider and longer than the prothorax, the 
punctures coarser, deeper and less close-set, partially serial in 
arrangement toward base especially toward the scutellum; abdomen as 
wide as the elytra, otherwise similar. Male with the fifth ventral 
feebly sinuato-truncate posteriorly, much more feebly sinuate at the 
middle than in pacificum, the notch of the sixth more parallel-sided, 
nearly as in Paederus, fully twice as deep as wide. Length 8.3 mm.; 
width 1.88 mm. British Columbia.............--Vancouveri 0. var. 
Elytra shorter than the prothorax and usually but little wider, the body 
more slender and much more parallel, black, the elytra somewhat pice- 
ous; legs pale, the antennae dusky; head longer than wide, as wide as 
the elytra, the eyes moderately prominent, the punctures strong, deep, 
moderately close-set; prothorax more or less distinctly narrower than 
the head, much longer than wide, the sides feebly converging toward 
base, broad'y arcuate especially anteriorly, the punctures rather large, 
strongly impressed, not very close-set, aggregated as in paciflcum, 
the aggregation along the smooth line usually broadly impressed 
posteriorly; elytra barely as long as wide, rather depressed, the sides 
feebly diverging as arule, the punctures strong and close-set throughout, 
arranged without order; abdomen as wide as the elytra, finely but 
strongly, closely punctate. Male with the fifth ventral broadly, feebly 
sinuate toward the middle, the sixth with an abrupt and very deep tri- 
angular emargination, not quite twice asdeep as wide, its angle broadly 
rounded; female differing but little from the male in general form, the 
sixth ventral very broadly, feebly arcuate at tip. Length 8.7 mm.; 
width 1.28 mm. Southern California and Nevada (Reno) to British 
COOUINUIAS ous hes Cidddvnds se Seve tsa vess icencsk ves sQhliernieum: Lec. 
6— Head inflated posteriorly, the sides behind the eyes parallel and 
distinctly arcuate; pronotum highly polished throughout, never aluta- 
COOUS 6:6 Fase hese s sesh ends esdediccseveeceeenebeesss eentebsseea sewase F 
Head not inflated posteriorly, the sides parallel or nearly so and usually 
straight for some distance behind the eyeS.....c.-sceseecccscessesee 9 
7 — Male with the apex of the fifth ventral transversely and rectilinearly trun- 
cate, with a minute triangular tooth at the middle. Body moderately 
stout and convex, polished, black throughout, the legs pale, the antennae 
dusky; head but slightly longer than wide, equal in width to the elytra< 
the punctures coarse, deep and well separated; lateral tumid ridge 
strong; eyes scarcely at all prominent, almost entirely visible from 
above; neck wide, fully three-fifths as wide as the head; prothorax 
large, slightly elongate, not very much narrower than the head, parallel, 
the sides feebly arcuate; punctures rather coarse, impressed and some- 
what close-set throughout, the median smooth area distinct; elytra but 
little longer than wide, only slightly wider and longer than the protho- 
rax, parallel, not very coarsely but deeply, very closely and confusedly 
punctate; abdomen as wide as the elytra, finely, densely punctate, 
more minutely but rather less densely so beneath. Male with the fifth 
ventral unimpressed, the sixth with a large triangular notch much deeper 
than wide, with the angle finely acute and the edges broadly and grad- 
ually beveled, the adjoining surface anteriorly not much modified, nor- 
