356 NOVITATES ZOOLOGICAB XXIII. 1915. 



radial (R 1 = 6) either arises from the cell or is stalked with the preceding vein 

 ( = C + SC 2 = 7 + 8), the stalk being usually short, but sometimes of considerable 

 length. R 2 and R 3 are sometimes on a short stalk in the fore- or the hindwing. 

 The most interesting aberration in our series of S. aegrota is a specimen in which 

 R 1 and R 2 of the forewing are coincident on both the right and left forewing, there 

 being one vein less than in normal specimens, and the vein representing R 1 + R 2 

 arises in the centre of the discocellulars at the point, or a very little below it, where 

 the central cell-fold ends. In the right wing of this specimen an oblique vein runs 

 from near the upper angle of the cell to R 1 + R 2 , joining this vein at one-third. In 

 the same wing the costa anastomoses with the first subcostal branch, while R 2 

 of the left hindwing is stalked with R 3 and becomes obsolete before reaching the 

 margin. 



The female is entirely wingless, and its thorax very short and modified. I 

 expect that some differences between the groups A, B, and C will be found to exist 

 in the thoracic sclerites. 



The genital armature of the male is of a very simple kind, and of great 

 similarity in all three groups, being most distinctive in Group A. I have not found 

 any differences between large and small, pale and dark specimens, or between 

 examples from different countries (Marocco and Palestine, for instance). 



The tenth tergite terminates in a short process which is nearly straight in a 

 lateral view, with the exception of the apex, which is slightly curved downwards. 

 In a dorsal view (PI. VIII, fig. 25) it appears club-shaped, being widened apically. 

 The dorsal surface is longitudinally impressed, and the apical margin is ronnded- 

 emarginate, not being produced centrally into a point, as in Groups B and C 

 (PI. VIII, fig. 24, anal view). The flanks of the tenth tergite proximal! y to the free 

 process extend downwards, meeting a transverse brown sclerite at some distance- 

 below the central process (PI. VIII, fig. 26). This plate, which is studded with 

 minute granules, is the modified terminal portion of the rectum. It is convex on 

 the upperside and concave beneath, being more or less closely applied to the 

 cylindrical penis-sheath. The latter, which slightly tapers apically, projects from 

 a simple collar. The lateral claspers of the ninth segment are much longer than 

 broad, being of nearly even width from the base to the strongly-rounded apex 

 (PI. VIII, fig. 26). The ventral margin of this valve is convex, the apex some- 

 what incrassate on the innerside, and the dorsal margin concave. On account of 

 this shape, the valves do not touch one another dorsally except near the apex, the 

 tenth tergite remaining visible in between them. 



GROUP B 



We have 340 males of this group, but no females. All are from Algeria : 

 Alger, Blida, Batna, and Guelt-es-Stel. The forewing varies in length from 9-5 to 

 14*5 mm., the majority of specimens measuring from IPS to 13 mm. If not too 

 much worn, both wings have prominent dark brown vein-streaks. The thorax 

 varies from dark mummy-brown to pale wood-brown. The extreme individuals are 

 rather different in aspect, but no line of demarcation can be drawn. The obvious 

 conclusion is that our specimens represent one species only, which conclusion is 

 confirmed by the study of the structure. The name of this species is S. infuscata 

 Klug (1832). 



The process placed at the lower edge of the frons (PI. VII, figs. 3, 4) is 



