1899.] NATURAL SCIENCES OF PHILADELPHIA. 421 



similar to that described and figured by de Saussurc as occurring 

 on the second segment of Z. lohxdatm; and the coloration of Z. 

 thoracicus and lohulatus seems to be very similar. But the fact 

 that lobulatm has the pronotum spinose laterally, and with a short, 

 coarsely jjuuctured thorax, shows that they are not closely related. 

 In the length of thorax, Z. thoracicus differs from all the other 

 species in the present collection. 

 Zethus ferrugineus Sauss. 



Four specimens from Santarem. These specimens differ from the 

 description in some points of coloration, and as no structural 

 characters whatever are given by de Saussure, I am not certain 

 that these specimens really represent Z. fernujineus. 

 Zethus chrysopterus Sauss. 



A single specimen from Santarem. Z. sculpturalis Smith is 

 probably identical with this species. 

 Zethus rugosiceps n. sp. 



Black; spot at sides of clypeus, dot behind each antenna, in 

 emargination of eye, short stripe on mandibles near base, scape 

 beneath, pronotum anteriorly, base and apex of teguhv, line on 

 postscutellum ; spot near apex of four anterior femora beneath, 

 stripe on their tibiae, line at apex of petiole and a slender one 

 before apical margin of segments 2 and 3, yellow; wings sub- 

 hyaline, darker in marginal cell, and slightly stained with yellow. 



?. — Head coarsely rugoso -punctate including cheeks and front; 

 clypeus a little less coarsely punctured, convex, not quite twice as 

 broad as long, the fore margin smooth, broadly subtruncate or 

 incurved; flagellum clavate; scape about as long as pedicel and 

 following three joints united ; space between hind ocelli equal to 

 or a little greater than that between them and eyes; pronotum 

 cristate, spinose at sides, rugoso-punctate ; dorsulum with coarse 

 separated punctures with a raised line anteriorly in the middle, 

 and two short, indistinct, impressed lines posteriorly ; postscutellum 

 sharply carinated at sides and with a short tooth-like carina medi- 

 ally; middle segment concave, the concavity smooth and bounded 

 externally by a sharp carina, beyond which the middle segment is 

 rugose as far as and slightly beyond the sharp lateral carina; stem 

 of petiole fully as long as hind coxa and trochanter, the enlarged 

 portion elongate-ovate with large separated punctures; the petiole 



