1870.] 299 [Burgess. 



a little upward; it is also bent pretty strongly inward with a very slight 

 curve; it is nearly uniform, tapering slightly on the outer half, the 

 extremity curving downward and slightly rounded, the apex and 

 apical portion of the inner edge armed with very minute denticulations, 

 directed inward; basal process directed at first upward and backward, 

 the posterior portion bent pretty strongly downward; but just beyond 

 the base it turns abruptly at nearly right angles backward, and extends 

 subparallel to the blade for some distance, developed as a subspatulate, 

 slender plate ; the whole rounded tip and the inner edge are armed, the 

 former with minute, the latter with heavier serrations. Lobe developed 

 as an extension of the upper posterior angle of the main body, directed 

 backward and upward, and curved also inward, of nearly uniform 

 breadth, twice as long as broad, the tip broadly rounded; the upper 

 edge of the main body is strongly, broadly and roundly excised at 

 the base of the lobe. 



Right clasp : Main body similar to that of the opposite side but slen- 

 derer. Blade quite similar to that of the opposite clasp, very slightly 

 broader, and beyond the middle expanding slightly instead of dimin- 

 ishing, the tip itself tapering, rounded, and with the outer half of 

 the inner edge very delicately denticulate ; basal process broad, tri- 

 angular, bluntly pointed, directed backward, curving over inward, 

 armed with very minute and very distant serrulations. Lobe devel- 

 oped as a somewhat similar, rather longer plate, more strongly curved 

 inward, directed upward and unarmed, the main body deeply and 

 roundly excised at its anterior base. 



California, H. Edwards. 

 Nisoniades Tibullus nov. sp. Fig. 12. 



Upper organ : Main body rather slender, short and high. The 

 crest is composed of a pair of small, broadly rounded, prominently 

 raised, united alations, inclined toward each other at more than a 

 right angle, each facing backward, upward and a little inward, a 

 little gibbous and supported by a sharp, elevated ridge running from 

 either side of the anterior part of the main body ; they are completely 

 covered above with longer and shorter spinules, developing, on the 

 upper edge, into quite long, curving, bristly hairs, arranged, when 

 viewed from above, somewhat in the form of a horseshoe. Hooks 

 short, very stout and broad, very widely separate at base, slightly 

 divaricate, asymmetrical, with occasional, more or less developed, lat- 

 eral denticles ; dependent from the ridge uniting their bases is a very 

 short and broad, appressed, fabiform tooth, its edges a little raised. 



