141 
The following key makes extensive use of the characters of the male, 
without Vhich the species could scarcely be identified with any certainty. 
The females may be determined by comparison with the males. The 
classification is based on the excellent monograph of Dr. Horn, “Review 
of 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. Smith’s 
studies of the sexual structures, “Notes on the Species of Lachnosterna 
of temperate North America, with Descriptions of New Species,” in Proc. 
U. S. Nat. Mus., v. 11, p. 481. 
1 Surface clothed with scales, subopaque; male with ventral segments 
carinate at middle, hind tibise with both spurs free, and hind tarsi 
long and slender; female apterous; antennas 10-jointed. 13-17 mm- 
lanceolata , Say 
Surface above glabrous. 2 
Surface above pubescent or hairy. &3o 
2 Antennae 10-jointed.. 3 
Antennae 9-jointed. 4 
3 Fixed spur of hind tibia short; metasternum hairy, penultimate seg¬ 
ment 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 emargi- 
nate; 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 small 
notch at each end from the sides of the impression, which terminate 
posteriorly in thick projecting angles. 14-19 mm. ephilida, Say. 
Fixed spur long or moderately long. 6 
4 Inner spur of hind tibia of male anchylosed. 5 
Inner spur of male free. 35 43 
5 Fixed spur of male short; clypeus deeply emarginate; elongate cylin¬ 
drical, pale yellowish testaceous, head darker; abdomen of male flat¬ 
tened at middle, last ventral irregularly concave. 10.5-13 mm. 
longitarsus, Say. 
Fixed spur at least moderately long. 
6 A marked sinuation at end of male hind tibiae, at base of fixed spur, 
in line with under surface of tibia. 7 
No distinct sinuation at apex of hind tibiae as described.11 
7 Subcylindrical, slender, yellowish testaceous, thorax and head darker; 
claw tooth small; penultimate ventral of male abruptly declivous at 
middle. 10.5-13 mm. glcicilis , Burm. 
Oblong oval, darker; claw teeth strong.... 8 
8 Fixed spur boot-shaped; clypeus feebly emarginate; thorax rather 
coarsely and sparsely punctate; penultimate ventral of male obliquely 
plicate each side of the middle, last segment with a deep concavity 
limited behind by a sharp elevated margin overhanging posteriorly. 
12-17 mm. gibbosa, Burm. 
Fixed spur of usual form. 9 
9 Abdomen of male at middle hairy and rather deeply channeled, last 
ventral with a rather smooth triangular impression, hind margin 
with a broad emargination, prolonged at middle in an acuminate 
point up the middle of the triangle, and closed by paler membrane; 
thoracic punctures coarse and close, denser anteriorly, a smoother 
median space. 17-18 mm. hirtiventris , Horn. 
Abdomen glabrous at middle.10 
