358 NOVITATES ZOOLOGICAE XXIII. 1916. 



veins are denuded and therefore appear whitish in certain aspects. S. chretieni 

 «an easily be distinguished from S. aegrota and S. infuscata by the forefemur and 

 the nenration. 



The process projecting from the lower margin of the frons (PI. VII, fig. 5) is 

 similar to that of S. infuscata, and, as in that species, sometimes is triangular, 

 in which case the two apical prongs or teeth usually present are obliterated. The 

 central scar of the frons is only visible if the hair is removed. It generally consists 

 of a double or single very low ridge in the shape of a horseshoe open anteriorly ; 

 in some specimens the scar is represented by a double raised central line, in others 

 the scar is distinct only at the interantennal suture. The individual variability 

 is very considerable (cf. figs. 13-15). I do not think that Groups B and C present a 

 reliable difference in the shape of the scar. 



There is apparently also no difference between S. chretieni and S. infuscata in 

 the spines of the abdominal tergites. The forefemur, however, which is flattened 

 beneath as in S. infuscata, and bears at the innerside a ridge dividing the under 

 surface from the lateral one, has at the apex towards the innerside ventrally a 

 triangular, transversely placed tooth, which is variable in size, and absent from the 

 other two species (PL VIII, fig. 23). The foretibia is slenderer than in S. infuscata, 

 and the proximal portion from the knee-joint to the base of the apical claw is 

 slightly longer. The stiff hairs on the inner surface of the forefemur are usually 

 dark brown, sometimes pale. 



The shape of the forewing varies inasmuch as the costal margin is either 

 nearly straight or distally more distinctly curved forward. Vein R 1 ( = 6) always 

 arises from the angle of the discocellulars, being a direct continuation of the 

 vestigial cell-vein (PI. VIII, fig. 20). In this character S. chretieni is more ancestral 

 than the other species of Somabrachys. The variability in the neuration of our 

 series is not considerable. The most noteworthy case is that of a specimen (from 

 Ghielt-es-Stel), in which R 1 of the left forewing sends out a branch which does not 

 reach the margin, while in the right forewing R 1 is connected by an additional 

 cross-vein with the lower cell-angle, and by another with the last subcostal vein. 



The male genitalia are of no great help in distinguishing S. chretieni from 

 S. infuscata. The apex of the tenth tergite is less suddenly bent downwards, and 

 the apical point is longer (PI. VIII, fig. 29, dorsal view) ; moreover, the clasper is 

 longer and narrower, and its dorso-apical margin thicker (PI. VIII, fig. 28). The 

 upper surface of the tenth tergite is either convex, or longitudinally impressed. 



To sum up, my conclusion is that we have only three species of Somabrachys. 

 It remains to be seen whether Oberthür really has more species, which I doubt. 

 Having ? ? of one species (S. aegrota) only, we assume for the present that the 

 distinctions in the $ $ (apart from the wings and genitalia) of S. infuscata and 

 S. chretieni apply likewise to the ? ? . If the assumption is correct, the ? of 

 S. infuscata can be recognised by the absence of a prominent central frontal process, 

 and of an apical tooth on the forefemur, and the ? of S. chretieni by the possession 

 of this femoral tooth. 



