Royal Physical Society. 113 



as in C. tristisj clothed with close-lying yellow hairs. The latter 

 is considerably broader than the elytra, more than one-half 

 broader than long, strongly rounded on the sides, the anterior 

 angles rounded, the posterior angles obtuse-angled, the posterior 

 margin cut straight, of the breadth of the elytra. These are 

 oblong oval, somewhat convex, densely and finely punctate, 

 indistinctly striated, brownish blue or purplish hoar-frosted, 

 with a yellowish pubescence along the base and basal margins. 

 The legs are brownish red. 



This variety stands in a very different position from those 

 which have gone before. They are so near the type, that they 

 might without much harm have been described as synonyms. 

 The present, on the contrary, differs in some respects widely 

 from the type, and it is by no means surprising that it has 

 hitherto been considered one of the best characterized and 

 most distinct species. 



The great breadth of the thorax is the prominent distinguishing 

 character ; its shape also is somewhat different, being nearer that 

 of C. nigrita, Erichs. The grounds on which I have deemed it a 

 variety of tristis, are first, that all the specimens of grandicollis I 

 have taken have been in company with tristis, and they were gene- 

 rally without the admixture of another species except rotundicollis, 

 which, as I have already said, I suspect to be another variety of 

 tristis. The examples of grandicollis were almost invariably males*, 

 and those of tristis for the most part females. In my earliest cap- 

 tures it so happened that I found nothing but males of grandicollis 

 and females of tristis, and naturally came to the conclusion that 

 they were the two sexes of the same thing. Subsequent researches 

 have convinced me to the contrary, as I have now a good many 

 male specimens of tristis, and one female of grandicollis. Still 

 the great preponderance is as I have stated, and the result to 

 which I have come is, that grandicollis is the normal form of the 

 male, and tristis of the female ; although, as is known sometimes 

 to take place in other orders of animals, the female occasionally 

 assumes the form of the male, or vice versa. Another ground for 

 concluding them to be the same species is their great general re- 

 semblance to each other, notwithstanding that the one has got 

 such a broad thorax, while in the other it is narrow. This simi- 

 larity is owing perhaps to the thorax in both being transverse, 

 and the rest of the body of the same figure. The pubescence, 

 colouring, wrinkling and punctuation are identical, and when two 

 fine fresh specimens with their pubescence and bloom untar- 

 nished are placed together, I think it is almost impossible to 



* Erichson founded his description on a " single male specimen." 



