SCUDDER. — NORTH AMERICAN TRYXALIN^. 51 



giiied with black laterally ; the male tegmina are shorter, generally much 

 shorter than the abdomen, with rare exceptions as long as the abdomen, 

 instead of being at least as long as, in macropterous forms considerably 

 longer than the abdomen, the vena plicata joining the vena dividens 

 before the middle or fading at some distance before the middle, instead of 

 running free past the middle of the tegmina. In general it is more 

 heavily marked, has shorter tegmina and slenderer antennse. lu the 

 female the tegmina are but little longer than the head and pronotum 

 together, sometimes no longer. It should at least be distinguished as a 

 7-ace ; future collections in the intermediate regions will probably show 

 more clearly whether it should be regarded as wholly distinct. 



7. PSOLOESSA AND SxiRAPLEURA. 



In his Revision of the North American Tryxalinje (Proc. Dav. Acad. 

 Sc, VI.), McNeill placed these two genera side by side at the end of his 

 series. Later, in my Preliminary Classification of the same subfamily 

 (Psyche, VIII.), I placed them at some distance apart, Psoloessa among 

 the Phlibostromse and Stirapleura in the Scyllinai. This change of mine 

 was wrong and came from incorrect observation of the foveolae of the 

 vertex (a distinction on which I placed a wider reliance than McNeill), 

 for in Psoloessa they ai'e partially visible from above, their plane beino^ 

 twisted feebly in relation to that of the margin of the vertex, so that while 

 they are visible from above on their inner half, they are not so on their 

 outer half. The other features of Psoloessa show that it belongs to the 

 Scyllinai, and I would restore it to the immediate vicinity of Stirapleura, 

 to which it is very closely allied. 



The table given by me for the separation of the genera of Scyllinfe may 

 be altered by substituting the following for the final paragraph relatino- 

 to Stirapleura (Psyche, VIII. 231) : — 



Pronotum constricted in tlie middle, the prozona slightly the shorter ; lateral 

 carin<e percurrent, more or less divergent in front and strongly divergent behind. 

 FoveoliB of vertex visible from above only on the inner half; lateral carinaj of 

 pronotum anteriorly but little or at least not strong!}' divergent, being gently 

 arcuate on the prozona ; lateral lobes of prozona feebly or not marked above tlie 

 middle with obliquely disposed short lunate carinules . . . Psoloessa Scudd. 

 Foveolffi of vertex visible from above throughout their length ; lateral carina of 

 pronotum very strongly divergent in front as well as behind, being strongly bent- 

 arcuate on the prozona; lateral lobes of prozona more or less conspicuously 

 rugose-carinate obliquely above the middle Stirapleura Scudd. 



