48 
lied to fusca, which are almost absolutely indistinguishable by any other 
means. One would naturally doubt the validity of such species, but on a 
careful study of these characters, I find them easily recognizable and sub¬ 
ject to but little variation, and have no doubt of the distinctness of 
the species based upon them. 
A very useful character is the sculpture of the last two ventral segments 
of the male, each species presenting its own characteristic pattern. The 
internal sexual structures of both sexes seem to be a reliable means of 
identifying species. The claspers of the male rest just within the opening 
at the tip of the abdomen, and may be easily drawn out and examined. 
It is desirable that specimens should be mounted with the claspers pro¬ 
truded. In the females and some of the males the two spurs at the end 
of the hind tibia are distinctly articulated and freely movable when 
fresh: but in a majority of the species the males have one spur firmly 
soldered to the tibia, appearing like an acute prolongation of the apical 
margin. The notch or sinuation at the base of this spur is ien stiong 
and distinct in congrua and hirtiventris , and least developed in gibbosa , which 
mav be immediately recognized, however, by its remarkable angulate spin. 
The antennal club of the male is usually much larger than that of the 
female. 
The antenna? are usually 10-jointed, three joints in the club and seven 
in the stem, but several species have normally only six joints in the stem, 
making the antenna? 9-jointed. Besides this, there is a tendency to lose 
one joint of the stem in one or even both antenna? of individuals of either 
group, which must be borne in mind and guarded against. 
Other distinguishing characters are found in the vestiture, color, and 
punctuation of the surface; the clypeus; the outline, margin, and basal 
channel of the thorax: the distinctness of the elytral costa?; the length 
of the antennal club: the teeth of the tarsal claws, etc. 
The following key makes extensive use of the characters of the male r 
without which the "species could scarcely be identified with any certainty. 
The females may be determined by comparison with the males. The clas¬ 
sification is based on the excellent monograph of Dr. Horn, •Ttevievv ot 
the Species of Lachnosterna of America North of Mexico,” in Trans. Am. 
Ent. Soc., v. 14, p. 209: and free use is made of Mr. J. B. Smiths studies 
of the sexual structures, “Notes on the Species of Lachnosterna of Tem¬ 
perate North America, with Descriptions of New Species, in Broc. u. S. 
Nat. Mus., v. 11, p. 481. 
1 Surface clothed with scales, subopaque; male with ventral segments 
carinate at middle, hind tibia? with both spurs free, and hind tarsi 
long and slender: female apterous; antenna? 10-jointed. 13-1, mm. 
Icinceolata, Say. 
Surface above glabrous..2 
Body hairy.^ 
2 Antenna? 10-jointed, inner spur of hind tibia anchylosed.3 
Antenna? 9-jointed.*.* 
3 Fixed spur short: metasternum hairy, penultimate segment with an 
elevated slightly roughened transverse ridge, narrowly. separated 
from the posterior margin. 15-16 mm. prcetermissa , Horn. 
Fixed spur of male wanting: metasternum nearly naked; slender, rufo- 
testaceous, shining: penultimate ventral segment of male rugulose. 
last ventral concave with two feeble cusps in the concavity. 
13-15 mm. glaberrima, Blanch.: 
Fixed spur short; similar to preceding, clypeus less distinctly emar- 
ginate: abdomen of male channeled, penultimate ventral with a de¬ 
pressed roughened space at middle, near hind margin, depression open 
behind, its floor with sharp blackish posterior edge, occupying 
a deep emargination of edge of segment, and separated by a smalJ 
notch at each end from the sides of the impression, which end pos¬ 
teriority in thick projecting angles. 14-19 mm. epiulida, bay. 
Fixed spur long or moderately long.* 
