798 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.xxiv. 
If Stuxberg'.s subgeneric divisions of Lithobius are based upon ten- 
able characters, then the major differences indicated above ought by 
analogy to rank these two species of Henicops in different subgenera. 
Descrij)tion. — Body increasing in width from the head backward to 
the region of the tenth doi'sal plate and then again becoming narrower, 
moderate. The cephalic plate sparsely hirsute with long and short 
bristles, the first dorsal plates hirsute subsimilarly to cephalic plate, 
the last few dorsal plates more sparsely provided with hair, the pos- 
terior median scuta subglabrous. The ventrum sparsely hirsute with 
long bristles, more densely posteriorly. Color yellow to brown, the 
first and the last dorsal plates usually darker, often reddish brown; 
head frequently very dark, its anterior and lateral portions reddish or 
chestnut, at times verging to black, middle and posterior portions 
paler; ventral plates smoky yellow; legs mostly 3^ellow, brown or some- 
what reddish brown toward extremities, the posterior pairs darkest; 
antennje yellow to brown, reddish brown or chestnut at base. The 
ground color in all parts subject to modification by a more or less 
strong violet or lavender tint apparently from deeper tissue, this being 
particularly strong in the head and in the anterior and the posterior 
dorsal plates. 
Head a little wider than long (ratio 12:11 or less); posterior margin 
truncate, as is also the narrower anterior margin, the sides convexly 
rounded; elevate except lateral borders, which are more or less 
depressed, flat, or concavic above. Antenna long, densely subpilose; 
articles 39 or 40, when ttO the ultimate articles proportionately shorter; 
articles short or very short, excepting the large second, and the more 
or less cylindrical, distally rounded ultimate article, the first three (or 
four) articles greatest in diameter, the fourth abruptly smaller, and 
the ten following subequal to it, very short, the fifteenth again 
abruptly smaller, those succeeding it gradually decreasing in diameter 
to the end, longer and more freely joined than those preceding. On 
each side of the head a round, moderately large ocellus at the bottom 
of a depression on the frontal suture. Prosternal teeth 3-3, small 
and pale, on each side the two innermost proximate and often elevated 
together, • the outermost being separated by a wider and deeper inter- 
val and the prosternal margin beneath it less produced. 
The posterior angles of the ninth, eleventh, and thirteenth dorsal 
plates strongly produced. Dorsal plates convexly arched; each of the 
larger scuta with five, more or less evident longitudinal sulci, two 
lateral, parallel one with each side, one median, and two intermediate 
diverging from each other posteriorly; the two lateral sulci continuous, 
with a transverse depression or furrow (sometimes double) running 
parallel with and a little anterior to the posterior margin, correspond- 
ing lines often traceable on the head. Ventral plates with one or with 
two wide and shallow transverse depressions. 
