II. ('. FALL. 14.") 



and much smaller than the labrura ; antennae 11-jointed (10-jointed 

 in Fuchsina), club usually 3-jointed, rarely 2-jointed. Prothorax 

 more or less crenulate or denticulate at sides and with nearly always 

 a rounded or transverse impression before the base. Body devoid of 

 cost;e, the hairs arranged serially on the elytra and either suberect 

 and bristling or much inclined. Front coxal cavities separated by 

 a prosternal lamina, which is often difficult to observe, the coxae 

 being frequently contiguous or subcontiguous on their free inner 

 faces, the cavities closed behind. Abdomen consisting of five or six 

 visible segments. 



Two only of the five genera recognized by Belon inhabit North 

 America, viz. : Corticaria and Melanophthalma. To these I have 

 to add a new genus — Fuchsina — based on a singular blind species 

 from California. 



As now treated in the books, Corticaria and Melanophthalma are 

 primarily separated by the number of abdominal segments ; Corti- 

 caria having six in the male and five in the female, while Melanoph- 

 thalma shows six in both sexes. This method of distinction serves 

 very well except for those species of Melanophthalma having a 

 2-jointed antennal club (subgenus Cortilena), in which, so far as my 

 observation goes, the sixth segment is visible in the female, but quite 

 uniformly concealed in the male. 



Our three genera may then be separated as follows : 



Antennas 11-jointed. eyes large. 



Abdomen of female with five segments, a sixth usually visible in the males; 



antennal club always 3-jointed Corticaria. 



Abdomen of female with six segments, that of the male also with six segments, 

 except in the subgenus Cortilena, in which the antennal club is 



2-jointed Melanophthalma. 



Antennae 10-jointed, eyes wanting Fuchsina. 



It should be observed that the so-called sixth ventral segment in 

 the males of Corticaria is probably, as suspected by Belon, not a 

 true segment of the abdomen, but only a part of the genital arma- 

 ture; and while usually sufficiently extended to be plainly visible, 

 it is not infrequently very indistinct or quite concealed. On the 

 other hand, this pseudo segment is occasionally revealed in the 

 female, and apparently with some constancy in one species (brevi- 

 cornis). In Melanophthalma the sixth segment is, perhaps, a true 

 external sclerite, at all events it is almost invariably present (except 

 as above noted), and its visibility is seemingly independent of the 



TRANS. AM. ENT. SOC. XXVI. (19) NOVEMBEK, 1S99. 



