Horn. ] 542 [April 19, 
joint and the club ; these may be either five or four, so that in one case the 
antenne are 10, in the other 9-jointed.* In the latter case the front has a 
semicircular row of erect hairs after the manner of Scolytus, while in those 
with 10-jointed antenne this structure does not exist. The arrangement 
of the tubercles is also different in the two groups, this is spoken of further 
on. 
Our species may be tabulated in the folowing manner : 
A. Antenne 10-jointed. Elytra with tubercles around the declivity. 
Last two joints of maxillary palpi equal. Larger species. 
Declivity of elytra coarsely punctured, on each side trituberculate. .. - 
basillare. 
Declivity impunctured, on each side bituberculate..... .....sericans. 
Last joint of maxillary palpi longer than the preceding. Smaller species. 
Declivity on each side trituberculate and 
with a few coarse punctures. Front of <j bituberculate. .texanum. 
smooth. Front of ¢) quadrituberculate.......... sextuberculatum. 
Declivity on each side bituberculate, smooth..... ....quadrispinosum., 
Declivity not tuberculate nor margined............... .dinoderoides. 
B. Antenne 9-jointed. Elytra with tubercles on or near the suture. 
Declivity coarsely punctured, sutural striee deeply impressed posteriorly, 
the two diverging in the declivity, each partly surrounding an acute 
juxta-sutural acute tubercle..... geno oC saosood oC ....bidentatum. 
Declivity smooth along the suture, and at the upper part a small acute 
tooth formed by the sudden elevation of the suture........declive. 
Declivity smooth along the suture, the latter slightly triangularly ele- 
vated at the middle of the declivity............. *...-....-suturale. 
S. basillare Say, (Apate) Journ. Acad. ITI, p. 321; ed. Lec. I, p, 181- 
A common species in the Atlantic States and at times very destructive to 
hickory-wooa. 
The characters in the table will readily distinguish it from any other, 
excepting possibly tevanum, the palpi being at times difficult to observe. 
It is however larger in size and with the declivity more coarsely and 
densely punctured, The absence of any tubercles on the head may however 
be a sexual character. Length .24 inch; 6 mm. 
S. sericans Lec. < Proc. Acad. 1858, p. 73; asperwm Lec. 9 loc. cit. 
A rather more robust species than basillare, with the elytral punctures 
becoming gradually coarser from the base to the declivity. The apex is 
rather abruptly declivous and impunctured and with two tubercles ou each 
side, the upper being the more prominent. Length .24 inch ; 6 mm. 
The male has a vertical tooth arising from the upper side of the left 
mandible. 
Occurs from from Texas to Cape San Lucas. 
* Nore.—These species bear the same relation to the 10-jointed Sinozxy/on that 
Enneadesmus does to Xylopertha, Another parallel case will be found further 
on. 
