AMPHICRANUS. 289 
the two sexes those forms which have respectively a black and a sanguineous prothorax. 
It may be so. Without some clue as to the possibly sexual nature of features, such as 
the peaked prothorax of A. fastigatus, it is necessary to include in the genus forms 
which in time will probably be separated therefrom. 
If Steganocranus, Kichh., be distinct from Amphicranus, it must be so by virtue of 
its broadly triangular antennal club, which is probably characteristic of the female. 
Examples of Amphicranus are rarer in collections than those of any other considerable 
genus of the family ; this seems to be due to their retired habits. These insects bore 
into large trunks, and are only to be obtained when sitting in the mouth of the burrow, 
or, more rarely, crawling on the outside of the tree. 
The collection of the late Alexander Fry, made during a long residence in Brazil, 
contains only eight examples; and four species alone in the genus are known to me 
by more than single specimens. 
The species are exclusively Neotropical. Five have been described, of which one is 
Mexican. A synopsis follows of all known to me; they amount to nineteen, of which 
twelve are from Central America. 
1. Sutures of the club strongly curved or angulate . . . . . . . « 2 
Sutures subtransverse, club usually small, not densely pubescent . . II. 
2. Prothorax strongly but not abruptly declivous in front, uniformly 
asperate 2. eee ee ee ee ee ee 8 
Prothorax subabruptly declivous in front, with a transverse callus at 
the summit of the declivity, the asperities aggregated into irregular 
ridges . - oe eee Loe ee 8. 
3. Anterior opening of the prothorax trisinuate or emarginate in front 4., 
Anterior opening not trisinuate or emarginate . . . . . «. «© « 5. 
4. Elytra explanate behind and not divaricate at the apex of the suture, 
the sutural angles sharp. . . . . Loe ee Le . [retusus, Eichh.] 
Elytra divaricate at the apex of the suture, the sutural angles rounded. [thoracicus, Kr. ] 
5. Elytra not divaricate at the apex of the suture, black, the prothorax red. [fryi, sp. n.] 
Elytra divaricate at the apex of the suture . 
6. Base of the protharax transversely strigose in the middle, elytra black. 7. 
Base of the prothorax punctate in the middle, basal half of the elytra 
rufous; underside and legs pale . . . . . . balteatus, sp. n. 
7. Margins of the elytral excavation with two teeth on n each side abdo- 
men ferruginous .. . re . « « . « elegans, Hichh. 
Margins of the excavation with three or more teeth on each side; 
abdomen dark . .. . . . . .  [politus, Eichh. ] 
8. Prothorax and elytra rufous, with ‘the apices s abruptly black . . « . bGelti, sp. un. 
Prothorax and elytra black or fusco-piceous, some spots on the former 
and the base of the latter testaceous. . . - - 1 we 6 ew ee 
9. Inner face of the apical elytral process unarmed . . . . . + - . 10. 
Inner face of the process with a conical spine. . . - . .  [bipunctatus, Kichh. |: 
BIOL. CENTR.-AMER., Coleopt., Vol. IV. Pt. 6, June 1905. 2 PP 
