SILIS. 95 
9. Silis lineata. 
Parallela, nigro-picea, nitida ; capite et prothorace flavis, nigro-vittatis; elytris nigro-piceis, angulo humerali 
flavo ; vel flavis, sutura apiceque nigris. Long. 6-7 millim. dQ. 
Mas prothoracis lateribus ante angulos posticos biexcisis. 
Femina prothorace antice angulato, margine ad angulum incrassato. 
Hab. Guaremaua, Cahabon, Cubilguitz, Chiacam, Balheu, Teleman, San J oaquin 
(Champion). 
This little species is nearly of the same size as S. basalis. The thorax is marked with 
a straight narrow vitta; and the head has a spot on the crown. The antenne are black 
to the base, rather more than half as long as the body, longer in the male. In the male 
the thorax appears bidentate on the sides; the incision is not very deep, and the hind 
angles are not acutely produced in either sex. The elytra are usually pitchy black, with 
the humeral angle above yellow ; two or three raised lines are faintly visible. Varieties 
occur in which the yellow extends itself along the margin, or occupies the greater part 
of the wing-covers ; the apex and the suture appear always to remain black. 
Section II. Maris prothorax processu duplici lamellato marginali.—Diremnvs, Leconte. 
10. Silis distorta. 
Nigro-fumosa, subopaca; epistomate, thoracis marginibus, abdominisque maculis lateralibus flavis ; thoracis 
disco nigro, nitido, rufo-cincto, profunde fossulato. Long. 5-6 millim. ¢ Q. 
Mas prothoracis lateribus processu duplici laminato, posteriore contorto, disco profunde foveolato impunctato. 
Femina prothorace magis orbiculato, juxta angulum posteriorem minute exciso. 
Hab. Guaremata (Sallé), Aceituno, Duefias, Zapote (Champion). 
The extraordinary lamellar processes from the side of the thorax, in the males of this 
and some other species, would seem at first to warrant their generic separation ; but it 
is to be observed that the various species of Sidés all differ in the mode in which the 
thorax is notched or sinuate, and that all the American species I have seen differ from 
the type (8. rujicollis), which is a European form. While the present species retains the 
principal characteristics of Leconte’s genus Ditemnus, it is plain from his description 
that the shape of the processes and notches differs, and that it also differs in some 
respects from Westwood’s genus Pachymesia. ‘The head presents nothing unusual; the 
antenne are half the body’s length, not, or scarcely, serrate in either sex. The thorax 
of the male is slightly emarginate in front; the round anterior margin then forms the 
first process, which is produced backwards in a lunate form, so as partly to cover the 
hinder one. The latter is produced from a detached portion of the margin in a parallel 
direction; behind it the thorax is constricted. The disk is deeply foveolate, the fovea 
being pointed in front and behind. In the female this fovea is only represented by an 
irregular double depression. Elytra leaden black, with a greyish pubescence, their 
margin sometimes exceedingly narrowly white in the middle. Legs black; abdomen 
black, sometimes each segment with a yellow spot on the side. 
