2 D. Sharp. . 



A. Dytiscidae. 



1. Synchortus aciculatus Sharp (d* = S. simplex Sharp). The 

 series from the White Nile are of a paler yellow colour, with 

 livid elytra, and the female has the rugosities of the elytra much 

 less marked than the original type. Dr. Regimbart is of opinion 

 (Mem. Soc. ent. Belgique IV, p. 120) that the species in this 

 genus are variable, and it is well therefore to treat these speci- 

 mens as the same species as the Insect from the Gaboon. S. aci- 

 culatus and S. simplex are doubtless the sexes of one species, as 

 was originally considered probable by me. S. asperatus and S. 

 duplicatus are the sexes of another species. S. sparsus is so 

 different, that it may prove to be really distinct. Dr. Regimbart 

 has recently described (1. c. p. 121) a species from the White 

 Nile, but it is evidently different from the series found by the 

 Entomologist of The Swedish mission in the same river. 



These specimens of 8. aciculatus vary in length from 3 — 3 5 /$ 

 mm. In the smaller specimens of the female sex, the asperate 

 punctures appear to be comparatively larger and closer than 

 they are in the individuals of superior size. 



23 specimens from the White Nile. G-ebel Ahmed Agha. 

 8 specimens N. of Kaka. March. 



2. Canthydrus notula Er. . All the specimens belong to the 

 variety with a yellow mark at the side very near the base of 

 the elytra. This mark varies in size, being sometimes merely 

 a short line, while in other cases it is more extensive and of ir- 

 regular form, but in no case is it as broad as it is long. Except 

 for this, there is little variation; the male has the head more 

 broadly and brightly red than the female. 



Four specimens among waterplants on the shore S. of Goz 

 Abu Gomr; one specimen from backwater near the River of the 

 White Nile north of Gebel Ahmed Agha; twelve specimens on 

 waterplants Gebel Ahmed Agha; four specimens from the White 

 Nile N. of Kaka. 



3. Canthydrus xanthinus] Reg. (Mem. Soc. ent. Belgique IV, 

 p. 127). One specimen. Gebel Ahmed Agha. March. 



Already recorded from Somaliland by its describer. 



