PTEROCYCLON. 269 
these species belongs to Ferrari’s genus Cosmocorynus’, which cannot be separated from 
Pterocyclon by any non-sexual characters discoverable without dissection. Trypocranus, 
Eichh. 11, appears to be allied to P. ferrarii or P. fimbriaticorne. It is an imperfectly 
diagnosed genus, and the structure of the mouth-parts, as described by Eichhoff, is so 
abnormal as not to be accepted without confirmation. 
The nomenclature of the genus must be touched on. Erichson!, after diagnosing 
Corthylus, indicated as its components Sostrichus compressicornis, Fabr., and 
B. fasciatus, Say. He stated that the funiculus was one-jointed, and as this is true 
of B. compressicornis, that species is accepted as the type of the genus Corthylus. 
B. fasciatus has a two-jointed funiculus, and was therefore removed by Eichhoff to 
the present genus. In 1866 Kirsch? described a species of Pterocyclon under the 
name Monarthrum chapuist; his generic diagnosis does not essentially differ from 
that of Erichson, and he repeated and preserved in his generic name the same error 
of regarding the funiculus as one-jointed. He simply reproduced the faulty part of 
Erichson’s work, and, as Eichhoff has pointed out 9, his genus is not valid, and the name 
Monarthrum has no claim to priority, being, if anything, a synonym of Corthylus, s. str. 
It was accepted by Leconte®, who again failed to detect the two joints in the 
fnniculus, and has become current with American entomologists. 
The species which Ferrari describes in his subgenera, Corthylus, s. str., and Micro- 
corthylus, together with Pseudocorthylus glabratus, Ferr., fall into this genus; his 
other species of Pseudocorthylus belong, as before mentioned, to Corthylus proper. 
His genus Corthylomimus was indicated for P. fasciatum (Say) and P. scutellare (Lec.), 
both of which he admits to not having seen ; it wholly fails. 
Cosmocorynus, Ferr., has already been mentioned ; this name is prior to Pterocyclon, 
but is better not employed for the whole genus, as it indicates certain aberrant forms 
which will probably come in time to be separated under Ferrari’s name. LEichhoff is 
the first observer who has accurately delimited and defined the present genus ®!°, and 
his name is adopted. 
The species of Pterocyclon are tolerably common in America; four occur in the 
Western United States, extending downwards from Lake Superior. The habits of 
P. mali (Fitch) have been described by Fitch, and more recently by Schwarz and 
Howard. We record twenty-three species from Central America, of which nineteen 
are new. ‘The following table is confined to the species of the Central-American fauna ; 
and it has been found desirable to separate the sexes in it under the characters afforded 
by the antenne. 
1. Antennal club without any fringe or fascicle of long hairs. (Males.) . 2. 
Antennal club fringed or fasciculate. (Females.) . . . . . . . 16. 
2, Elytra not sulcate along the suture before the declivity . . . . . 38. 
Elytra with a common sulcus almost from the base of the suture . . sulcatum, sp. n. 
