1906.] COLEOPTERA OF THE GENUS SCIOBIUS. 239 



of Curculioniclse from both Bothaville and Hoopstad, thei'e was 

 not a single Sciohius among them. 



Of the comparatively few species Avith whose habits I am 

 acquainted, the majority feed on low trees and shrubs; and on 

 the Natal coast hrevicollis and histrigicolUs are among the 

 commonest beetles to be obtained by general beating. On the 

 other hand, the smallest species, and those with a predominance 

 of bright green colouring, appear to prefer herbaceous plants and 

 are generally obtained with the sweeping-net. 



The general type of colouring is black or reddish brown varie- 

 gated with gi'ey, whitish or yellowish scaling, which has a. faii-ly 

 constant tendency to form a denser lateral stripe, often accompanied 

 by a transverse band across the summit of the elytral declivity. 

 In only a few instances are bright colours to be found, and then 

 they are of a green or golden-green hue. There can be little 

 doubt that in every case the coloui-ing of these insects will be 

 found to have a simple procryptic significance. 



There is a well-marked sexual dimorphism in many of the 

 species, so that in one or two cases the sexes have been described 

 as distinct forms. But these sexual characters are often very 

 different in the various species, and the only one which is constant 

 throughout the genus (or, rather, thi-oughout the 24 species of 

 which both sexes are known) is the form of the last abdominal 

 segment. This is always more acuminate in the $ and is 

 usually slightly convex in the middle ; whereas in the S it is more 

 broadly rounded apically and proportionately more transvei-se, and 

 generally there is a more or less shallow central impression. 

 Another common character is the greater curvature of the tibia>, 

 especially the anterior pair, in the S . But in the case of obesus, 

 decdbatics, opalinus, 2^ollinosus, and marginatus, the tibise are 

 practically similar in the two sexes. In a few species, such as 

 hrevicollis, granosus, and pond^o, this distinction is specially well- 

 marked, the tibiae of the S being also broader and noticeably 

 compressed. In the great majority of instances, however, the 

 difference is comparatively slight. Horni presents a special 

 feature in that the anterior tibiae of the S are distinctly sinuate 

 internally. Another striking sexual character is to be found in 

 the rostrum, in which the genje of the <S are occasionally produced 

 into long, recurved, horn-like processes. But this is only the 

 case with granosus and cultratus. In listrigicollis and dealbatus 

 there is a similar production, only to a much less extent, and the 

 process is not recurved. In cinereus, scapularis, griseus, and 

 viridis the gense are only slightly more dilated in the c? than in 

 the ^ ; whereas in the remaining 16 species the sexes do not 

 differ in this respect. As a rule, the shape of the prothorax is 

 similar in the two sexes, but in hrevicollis, histrigicolUs, harheri, 

 marginatus, pondo, and iottus this segment is distinctly shorter 

 and more transverse in the $ ; in granosus its sides are more 

 strongly rounded in the c? ; while in cidtraius the central portion 

 is more elevated and smoother in the § than in the S . In the 

 majority of species the shape of the elytra varies considerably in 



