184 [August, 



This species is not abundant, and the series I have examined does 

 not exhibit much variation. In immature individuals the head and 

 thorax may be rufescent, but not very brightly so. There is no 

 tendency to the diminution of elytral punctuation, the character that 

 is so striking in 0. hrevicollis. In July and August, 1890 and 1891, 

 I met with a fine series of 0. rnfibarbis at Swaffhamprior in 

 Cambridgeshire on the Devil's Dyke, and Commaniler Walker finds it 

 not very rarely about Oxford. It also occurs not rarely near Chatham, 

 and Mr. Champion possesses a specimen from Mickleham. 



The application of the name rnfibarbis is conventional. Fabricius's 

 few words containing nothing characteristic ; but I make use of it in 

 this manner as involving the least change and inconvenience. 



3. — 0. cordatus, Duftschm. In this species the thorax is very 

 much rounded at the sides in front, and greatly narrowed behind, the 

 sides there becoming parallel for a short distance so that the angles 

 are quite rectangular ; there is a raised margin along the base, fine 

 but quite distinct. The punctuation of the upper surface is coarse, 

 and the colour is usually a pale brown or tawny inclining to piceous, 

 and sometimes red on the head and thorax. 



Although these characters render this species easy to distinguish, 

 nevertheless there is sometimes confusion between it and rtipicola : 

 the latter does not have the sides of the thorax behind truly parallel 

 and the base is not margined. The two species differ in various other 

 ways and the sedeagus is very different. 



0. cordatus is really nearer to 0. riifiharbis, but the last-named 

 species has the thorax much broader at the base and without a raised 

 margin there. 



The aedeagus of cordatus is very like that of rufibarbis, except for 

 being considerably shorter : and in the British list cordatus should 

 come next to rufibarbis, the distinction of the two as regards the basal 

 margin of the thorax being of less importance than the similarity of 

 the male organ. 



0. cordatus is decidedly a scarce insect in this country, and most of 

 the specimens in our collections come from the neighbourhood of Deal, 

 where it appears to vary but little. It is not however strictly a coast 

 species, and Mr. Champion's collection includes a specimen from 

 Mickleham, and tM^o from Croydon, and all these three individuals 

 differ so much from the Deal form that they might give rise to the 

 idea of a distinct species. These specimens are all female, and are far 



