1668. 



67 



4. O. bicolor, Payk. Oblong, the sides nearly parallel, convex, above 



bluish-black, shining, the sides brassy, the elytra punctate-striate, 

 all the striaj evident, but the internal rather finer than the external, 

 under-side black, inflexed margin of elytra and thorax, and legs 

 rufo-testaceous. Long. 3-j — 4"' ; lat. li — If". 



Tar. Extremity of abdomen and breast reddish. 



This species is distinguished by its elongate and parallel form, by 

 its very long elytra, the apices of which are more rounded than in the 

 allied species. Sometimes the extremity of the elytra is obscurely red. 



It appears to be rare, most of the specimens standing under this 

 name in our collections being the next-mentioned insect. Mr. Bold 

 has a few specimens taken in Durham, and there are also some in Mr. 

 Crotch's collection. 



5. G. distinctuSj Aube. Oblong, ovate, the sides sub-parallel, convex, 



above bluish-black, shining, the sides brassy, the elytra'punctate- 

 striate, all the striae evident, the internal finer than the outer, 

 especially towards the base, under-side black, legs and inflexed 

 margin of elytra reddish. Long. 2f — 3i'" ; lat. li— 



Vars. Colour above entirely black, the breast and extremity of abdomen 

 being sometimes red ; also differs considerably in size and form. 

 This is, I think, only a variety of the preceding (G. bicolor). The 

 characters by which it is said to be distinguished from it are, that G. 

 distinctus is smaller, with the sides more rounded, the elytra shorter, 

 and their apices not so rounded, so that the external angle is more 

 evident. Some of my specimens show all these characters plainly 

 enough, so that I do not think I am in error in calling them G. dis- 

 tinctus ; but, as variations in all these points occur. I think it will have 

 to be united with G. bicolor. 



Common in various parts of the country. Brighton, Deal, Edin- 

 burgh, Newcastle ; sometimes in brackish, sometimes in fresh, water. 



6. G. caspius, Aube. Oblong ovate, tolerably convex, above bluish- 



black, not very shining, the sides brassy, the elytra punctate- 

 striate, the internal striae very evidently finer than the outer, the 

 interstices obsoletely but thickly punctured, under-side black, 

 margins of thorax and elytra, extremity of abdomen and legs, red. 



Long. 31 ; lat. \\\ 

 This species very closely resembles the preceding, but it is not so 

 shining, and when examined under a good magnifying-glass, the inter- 

 stices are found to be obsoletely though thickly punctured ; whereas ia 



