1911., 81 



2. Legs and palpi pitcliy-tcstaccous or pitchy ; elytra black. 



A. Size larger. 



a. Form narrower and more elongate (like that of G.pen7iatus 

 and G. velox) ; antennae longer and not thickened to- 

 wards apex G. bishojn, Sharp. 



h. Form broader ; antennae shorter and distinctly thickened 

 towards apex G. keysia/iius, Sharp. 



B. Size considerably smaller ; first joint of antennae black ; head 



about as broad as thorax, somewhat rounded at sides... 



G. appendiculatus, Sharp. 



G. trossulus can hardly be mistaken for any of the other species, 

 the short and narrow elytra giving it quite a characteristic appearance. 

 The head is large and broad, and the antennae rather short, with the 

 penultimate joints slightly transverse. The thorax is often pitchy. 

 It does not appear to be by any means a common species, and is very 

 local. In Berkshire I have only taken it in flood rubbish from one 

 limited locality. 



G. nigritulus is recognised by its large size, broad head, long an- 

 tennse, of which the penultimate joints sometimes appear to be longer 

 than broad, and light palpi, legs and base of antennae. The elytra 

 are nearly always brownish. It is the most abundant species in 

 England. 



G. stipes is another species with a large broad head. It is of 

 about the size of G. trossulus, but is broader, and the elytra are ex- 

 ceptionally broad in proportion to the thorax. It is distinguished 

 from all its allies by the distinctly transverse penultimate joints of the 

 entirely black antennae. The legs are rather intermediate in colour 

 between those of the light and dark legged species. I have obtained a 

 good series of it by carefully searching among many hundi-eds of G. 

 nigritulus and G. pennatus from flood rubbish. G. pennatus is much 

 smaller and narrower than the three foregoing species, and has a pro- 

 portionately narrower head. The penultimate joints of the antennae 

 are about as long as broad. It is almost as common as G. nigritulus 

 in the south of England. 



G. velox. This is the most difficult member of the group, and I 

 am doubtful whether the ? can always be distinguished from the same 

 sex of G. pennatus. It appears to be a somewhat rare species. 



G. Jceysianus is one of the larger species, and somewhat resembles 

 the ? of G. stipes. It is, however, distinctly narrower ; the head is 

 narrower in proportion to the thorax ; the penultimate joints of the 

 antennae are much less transverse, although they are slightly so ; and 



