NO. 2130. NORTH AMERICA RHAPHIDOPHORINAE—CAUDELL. 657 



5. Posterior tarsus with four distinct segments 6. 



Posterior tarsus with but three distinct segments (fig. 25) Daihinia Haldeman. 



6. Second segment of the hind tarsus scarcely longer than the vertical depths, usually- 



less than twice as long as the third segment (figs. 22-24) 7. 



Second segment of the hind tarsus distinctly longer than the vertical depths, being 

 usually two times as long as the third segment (figs. 9, 16, 20) 8. 



7. Anterior tibiae armed above, about the middle, or a little beyond, on the inner 



margin with a distinct spine Udeopsylla Scudder. 



Anterior tibiae unarmed above except toward the apex 9. 



8. Vertex between the antennae armed with a declivitous hornlike protuberance 



(fig. 20) ; abdomen of the male more or less tuberculate or spinose above, some- 

 times conspicuously so (fig. 15) Pristoceuthophilus Rehn. 



Vertex between the antennae smooth or tuberculate but never with a declivitous 

 hornlike projection as above; abdomen of the male never distinctly tuberculate 

 or spinose above Ceuthophilus Scudder. 



9. All dorsal spurs of hind tibiae short and inarticulate Cnemotettix, new genus. 



Some dorsal spurs of hind tibiae longer and articulate 10. 



10. Last dorsal spur of the hind tibiae on the inner side separated from the preceding 



one by a distance two or more times as great as its own width (figs. 22, 23) 11. 



Last dorsal spur of the hind tibiae on the inner side separated from the preceding 

 by a distance no greater than its own width (fig. 25) Rhachocnemis, new genus. 



11. Posterior tibiae armed above, between each pair of movable spurs, with several, 



usually five or more, acute serrations Ceuthophilus Scudder. 



Posterior tibiae unarmed above between the dorsal spurs, or armed with but a few 

 tubercles or serrations, rarely ^vith as many as five tubercles between one or two 

 pairs of spurs, never with five or more serrations between each pair as in Ceutho- 

 philus (figs. 22, 23) Phrixocnemis Scudder. 



Unplaced Hemiudeopsylla Saussure and Pictet. 



Genus TROPIDISCHIA Scudder. 

 Tropodischia Scudder, Bost. Journ. Nat. Hist., vol. 7, 1862, p. 440. 



This genus differs so radically, especially in the armature of the legs, 

 from all other genera of the subfamily that Scudder quite properly 

 separated it as a distinct group. In general appearance it resembles 

 somewhat Diestrammena and Hadenoecus but is really allied to neither. 



Head moderate, as broad as the front portion of the pronotum; vertex 

 between the antennae forming a pair of rounded-triangular, laterally 

 flattened plates, not widely separated and about as long as the basal 

 height; antennae moderately long and slender; palpi with the terminal 

 segment about twice as long as the preceding one, one-fourth longer than 

 the third, gently enlarged apically and cleft beneath only in the tenninal 

 fourth or less. Pronotum noticeably broader posteriorly than anteri- 

 orly, the disk smooth and passing gradually into the lateral lobes with- 

 out a sign of lateral or median carinae; lateral lobes shallow, the lower 

 margins straight and horizontal, no humeral sinus; disk of pronotum 

 broadly rounded anteriorly, posteriorly truncate; meso- and meta- 

 notum together about as long as the pronotum and as broad as the 

 pronotum at its posterior margin, the lateral lobes equally deep as 

 those of the pronotum, the lower margins rounded, very broadly so 

 81022°— Proc.N.M.vol 49—15 42 



