OF NORTH AMERICA. 

 Genus, CTENUCHA, Kirby. 



"In this genus the front of the head is as broad as the distance 

 from the insertion of the antenna to the front edge of the clypeus, 

 being full and convex. Ocelli, large. Eyes, full and globose, of the 

 usual size. When denuded the clypeus is seen to be short and scutel- 

 late, as long as broad, rising between the antennae into a low obtuse 

 point. In front it sweeps rapidly away from the eyes, rising from 

 them, while the front edge contracts rapidly, the sides being slightly 

 excavated just behind the square sub-truncate front edge, which seen 

 from below is somewhat arched. On the surface is a slight mesial 

 ridge extending and increasing in size to the base of the piece. The 

 two pieces behind, viz: occiput and epicranium, are together in length 

 equal to ihe clypeus, so that the antennae are situated very exactly 

 midway from the base to the front of the head. The "vertex" of the 

 head is clothed with much longer scales than the frontal ones which 

 project out between the antennas. The occiput is regularly transversely 

 oblong, being about four times as wide as long. The epicranium is 

 narrow, sub-triangular, truncate in front; and at its base encroaches a 

 little upon the occiput, than which it is one fourth longer. The tri- 

 angular labrum is short, broad and obtusely pointed. Mandibles, 

 slender, being nearly twice as long as broad, not very acute, with long 

 setae converging over the maxills which are well developed, and when 

 unrolled reach to the base of the abdomen. The palpi are long and 

 slender, of good size, porrect, somewhat flexuous in their course, 

 curving downward at their base, and then rising a little, in front of the 

 head, while their tips are a little depressed. First joint nearly as long 

 as the second, with long depressed scales beneath, but generally the 

 scales are fine. Second joint twice as long as broad, and with the 

 third, which is a little shorter and acute, reaches out in front of the 

 clypeus." 



"Antennae, half as long as the primaries, with long, finely scaled, 

 pectinations, each of which bears a terminal setae. In the female the 

 pectinations equal in length that of the joints of the antennae." 



"Thorax, and body generally, stout and finely scaled. Patagia, 

 large, free from the tergum beneath, reaching behind nearly to the 

 posterior edge of the meso-scutellum, while its posterior scales reach 

 to the base of the abdomen. The prothoracic scales are orbicular, large, 

 and are unitedly broader than the head. Meso-scutum short, broader 

 than long, scutellum large and pentangular, the longest side being the 

 posterior edge, which is a little convex, and scarcely angulated in the 



