350 NOVITATES ZOOLOGICAB XXIIT. 1916. 



ON THE SPECIES OP SOMABRACHYS IN THE 

 THING MUSEUM. 



By KARL JORDAN, Ph.D. 



(With Plates VII. and VIII.) 



"TTT"E have over 900 males of Somabrachys in the Tring Museum, besides some 

 VV females and larvae. Most of the specimens are from various parts of 

 Algeria, a few from Marocco, Tunisia, and Palestine. As the present state of 

 Europe makes travelling outside England impossible for me, I have not been able 

 to consult any Continental collections ; and, to my great regret, Monsieur Charles 

 Oberthiir has been so seriously ill that he was prevented from sending me samples 

 of his species. May the fates be kind to Entomology and accord him a complete 

 recovery. 



The specimens of Somabrachys have been separated into about twenty species 

 and varieties. The coloration being very uniform, the determination of the species 

 is a matter of difficulty according to Oberthiir. I agree with him even if there 

 are only half as many distinct species as have been described ; and I do not expect 

 that insectivorous enemies of Somabrachys, if any, are able to discriminate with 

 such nicety that their destructive activities have played a role in building up the 

 specific distinctions. 



What are these distinctions ? Some deviations in colouring, wing-shape, and 

 size are in the main the only characteristics relied upon by the authors of the 

 species, or, to be more correct, the authors of the names. 



The first substantial advance in our knowledge of the species is due to- 

 ll. Powell, who studied the caterpillars on the spot and bred many imagines. 

 The results of his studies, which are laid down in Oberthttr's Etudes Lep. Comp. 

 v. i. pp. 227-282 (1911), bear testimony to his fine powers of observation. 



Powell distinguishes three chief types of larvae : 



Group A. — Larva with slits on seven abdominal segments. 



Group B. — Larva with slits on eight abdominal segments ; dorsal warts 



of abdomen slightly oblique, bearing four, rarely five, long hairs, 



except on segments viii, ix, and x (last three segments). 

 Group C. — Larva with slits on eight abdominal segments ; dorsal warts 



of abdomen oblique and strongly transverse, bearing nine to twelve 



long hairs, except on segments viii, ix, and x. 



The imagines I have before me also fall into three groups, which are so 

 clearly defined that an error as to the position of a specimen, be it a c? or ? , is 

 hardly possible. The chief differences between these groups are found. in the head, 

 foreleg, abdomen, and wings. The c?-genitalia also differ to some extent (cf. 

 Plates VII and VIII). Having ? $ of one group only, we do not know if there 

 is any specific distinction in the armature of the seventh and eighth abdominal 

 sternites of that sex, but believe that little of diagnostic value is to be derived 

 from those segments in the present case. 



