Casey — A Revision of the American Paederini. 113 
wider than the prothorax but only very slightly longer, strongly though 
not very coarsely, moderately sparsely punctate, distinctly impressed 
along the suture; abdomen parallel, straight at the sides, distinctly nar- 
rower than the elytra. Male with the third and fourth ventrals just 
visibly impressed along the middle; fifth with avery deep elongate- 
oval, glabrous impression, not attaining the base, the apex feebly sin- 
uate at the middle; sixth not impressed, transversely, rectilinearly trun- 
cate at tip, with a small and acutely triangular notch, only slightly deeper 
than wide and an eighth or ninth as wide as the apex; female not at 
hand. Length 4.0 mm.; width 0.8mm. Massachusetts (Lowell), —Mr. 
F. Blanchard; [Florida — LeConte]........ bidescutubee - nitidulus Lec. 
Body colored as in the preceding, the elytra pale testaceous throughout, 
except a piceous-black cloud toward the suture and not quite extending 
to the apex; head nearly as in nitidulus throughout, the antennae more 
slender, with the medial joints fully one-half longer than wide; pro- 
thorax but slightly elongate, much wider than the head, a little broader 
and shorter than in the preceding species, parallel and feebly arcuate 
at the sides, the strong punctures rather less sparse; elytra small and 
depressed, not as long as wide, very slightly wider than the prothorax 
and much shorter, the sides diverging from the base, the punctures 
rather fine but strong, somewhat sparse; abdomen parallel and straight 
at the sides, fully as wide as the elytral apex, dull in lustre and densely 
punctulate as in the preceding species. Male with the third ventral un- 
modified, the fourth very feebly impressed near the apex only, the fifth 
with a small and very deep subglabrous pit, rounded in outline, ex- 
tending from a little before the middle to the apex, the latter feebly 
sinuato-truncate; sixth with an acutely angulate triangular incisure, 
deeper than wide, larger and deeper than in nitidulus and a seventh or 
eighth as wide as the apex, the latter anteriorly and outwardly truncate 
at each side; female not known. Length 4.5 mm.; width 0.75 mm. 
Massachusetts (Lowell), — Mr. Blanchard...... --+-parvipennis n. sp. 
The difference in general facies between the large-winged 
and short-winged species in all these genera of the Lathrobia 
being so pronounced, with most other characters so similar, 
has suggested’ the presence of dimorphism, but I have been 
unable to prove this in any one instance, and, indeed, the 
only useful evidence will be that gained by actual observation 
of the life history of the species. The normal sexual differ- 
ences in the elytra are not great, although nearly always 
observable, the elytra of the female being a little larger than 
those of the male, but, as can be seen in this genus, as well as 
in Tetartopeus lacustris, the presence of short winged forms, 
if not indicative of specific difference, must be due to 
perfectly asexual dimorphism, —a matter impossible to prove 
without careful biological study. 
