i8 93 .] THE BRITISH NATURALIST. 223 



The following table, adapted from Bedel, will serve to separate 

 our three species : — 



A. — Elytra with the seventh stria indicated by a row of 8 or 9 



punctures . . . . B. biguttatum, F. 



B. — Elytra with the seventh stria wanting. 



1. Size larger (4 to 5 mill.) ; joints 3 to 10 of antennae 

 three times as long as broad ; punctation of basal 

 half of elytra less strong . . B. tricolor, Bedel. 



2. Size smaller (3! mill.) ; joints 3 to 10 of antennae at 

 most two and a half times as long as broad; puncta- 

 tion of basal half of elytra stronger B. lunulatum, Fourc. 



The synonymy of these insects, as regards English and French 

 authors, appears to be the following : — 



B. BIGUTTATUM, F. (ijjg). 



= B. biguttatum, Fowler, Brit. Col. 



Cox, Handbook, 

 var. B, Dawson, Geodeph. Brit. 

 ,, v. B, Fairmaire et Lab. Fa. Ent. Fr. 



= vulnevatum, Dej. 

 B. iricolor, Bedel (1879), Fa. Col. Seine. I., p. 35. 



B. riparium, Fowler, Brit. Col. 

 B. lunulatum, Fourc. (1785). 

 = B. riparium, 01., et auct. 



,, Cox, Manual. 

 = B. biguttatum, Dawson, Geodeph. Brit. 



,, Fairmaire et. Lab. Fa. Ent. Fr. 



Bembidium biguttatum, F., may be readily known by the presence of 

 the seventh stria of the elytra. The first joint of the antennae and the 

 legs are usually of a clearer red, and the sub-apical spots better defined, 

 than in its allies. In size it is intermediate between the two other 

 species (3! to 4 mill.). It is common, though [less so than B, 

 lunulatum. 



B. iricolor, Bedel, is the largest species of the group, and is often of 

 a pitchy colour, though, like the others, iridescent in a strong light. 

 The sub-apical spots are much less distinct than in B. biguttatum and 

 are often diffused over the entire apex. The total absence of the 

 seventh stria of the elytra will at once separate it from B. biguttatum, 

 and its larger size, finer punctation, longer intermediate joints of the 

 antennae, and flatter and broader interstices of the elytra, will separate 

 it from B. lunulatum. I have only seen specimens which have been 

 taken near brackish water, and this agrees with Bedel's habitat for the 

 insect. I have captured it at Charlton and Southsea ; Mr. Heasler 

 has taken it at Plaistow, Plumstead, Rainham and Sheerness ; and 

 Mr. Lewcock also has taken it at Rainham, Essex. 



