1307.J 5 



and considers the above named four forms to be good species ; he 

 also includes many others not yet recorded from Britain in the 

 ritficollis group. I will offer no opinion on these conflicting views 

 beyond remarking that if immaculaius is not considered worthy of 

 specific rank, that of JluviatiUs can hardly be maintained. 



In all the British species of the group the males have the first 

 three joints of the anterior tarsi dilated, each joint being slightly 

 produced forward on the outer side; the intermediate tarsi are also 

 dilated. The females have the elytra alutaceous. 



The British forms may be distinguished thus : — 



I. — Thorax very short, more than double as broad as long, with strongly con- 

 verging sides ; elytra short and broad, with the greatest breadth just behind 

 shoulders, from thence narrowed to apex. 2-3 — 2"5 mm.... 



S. rujicollis, De Or. 



II. — Thorax less shoi't, at most twice as broad as long, with sides less convergent ; 

 elytra having its greatest breadth nearer middle, with the shoulders more 

 gently rounded ; body more oval and narrower than in rujicollis. 

 A.— Elytra broader, with sides more parallel for four-fifths of their length, 

 then rather abruptly narrowed to apex. 2'5 — 28 mm... 



H. immaculatus, Gerh. 

 A A. — Elytra narrower, with sides more convergent, gradually narrowed to 

 apex from about the middle. 

 a. — Black lines on elytra never interrupted near base, nor dilated into 



spots. 2 — 2*3 mm H. striatum, Sharp. 



aa. — Black lines on elytra interrupted in places, notably near base. 

 2 — 2"5 mm H.Jluviatilis, Aub^. 



//. immaculatus is far removed from rujicollis by being the most 

 parallel-sided of the group. The dark lines, in which are placed the 

 punctures, are broader and more conspicuous than those of striatus 

 and fluviatilis, and are very rarely interrupted ; the punctures them- 

 selves being larger and less closely placed than those of the two 

 latter species. Sometimes the dark lines are slightly dilated in 

 places giving an appearance of vague spots. According to Seidlitz 

 the species is more common than Jiuviatilis. The only British 

 specimens 1 have seen were taken by Mr. W . H. Tuck near Bury 

 St. Edmunds. 



12, Churchill Road, 



Dartmouth Park, N.W. : 



November \4th, 1906. 



