1910.] 107 



Closely allied to C. similata, but rather smaller (our svmilata average 

 li mm. long), with shorter, more oval elytra, more transverse thorax, much 

 shorter legs, and finer sculpture and pubescence on the elytra. The first joint 

 of the tarsus is in each sex thicker, and the second joint is inserted so far back 

 on the first joint that it scarcely projects beyond the end thereof and the tarsus 

 looks 2-jointed. In the male the front tibiie are dentate, but the little tooth 

 is placed so much at the back of the tibia (as in C. truncatella) that it is on 

 account of this, and the small size and short tibia, very difficult to detect, 

 whereas in the ^ of C. similata the tooth is very conspicuous. 



Found on an oak tree in the New Forest, in 1908 and 1909 ; first 

 detected l»_y Mr. C. G. Lamb in honour of whom the species is named. 



Tlie history of the discovery of tliis insect is of some interest. 

 [n August, 1908, Mr. C. Gr. Lamb brought me a small beetle he 

 had found on an oak tree here. It excited my interest as it appeared 

 to me when alive to look distinctly different from any of our 

 common Corticaria. I accordingly went with him the next day to 

 look for it, and was successful in securing on the same tree about 

 a dozen examples. On mounting and examining the specimens it 

 appeared to me that I had obtained a strongly dimorphic species, the 

 males being distinguished by a different shape and sculpture, and 

 having longer legs than the female, and also by the possession of a 

 denticle on the front tibia. 



At that time C. similata was supposed to be unique as British, 

 and on comparing Mr. Lamb's species with this unique it was clear 

 that the male sex agreed therewith. I therefore concluded that we 

 had rediscovered C. similata — after an interval of 37 years — and that 

 it was a highly dimorphic species. But I felt very much surprised 

 that the books said nothing as to a sexual dimorphism of form and 

 sculpture. I commiuiicated my discovery to Mr. Champion and was 

 agreably surprised to hear that he was finding C. similata at Woking, 

 and also that he had mentioned the fact in one of his numerous 

 lists of captures there. At the same time he sent me two specimens 

 of these Woking individuals ; they were males, and I consequently 

 asked him if he could let me see the dimorphic female (as I supposed 

 it to be). In reply he sent me for inspection his fine series, and I 

 found therein both sexes, the female resembling the male ! I again 

 therefore visited Mr. Lamb's tree to obtain more material ; and, 

 having succeeded, I examined it very carefully, and I found that I had 

 both sexes corresponding entirely with the Woking sexes of C. similata, 

 and in addition to these a few of my dimorphic female. A renewed 

 scrutiny showed that of this latter I had really also both sexes, it 



