THE CANADIAN ENTOMOLOGIST. 191 



where a somewhat similar conjunction is brought about, not so much by 

 the prolongation of the humeral spot as by the extension forward of the 

 sutural patch. 



Figure k represents a form of coloration sometimes seen in the male 

 of C. /oagipennis, Casey, of which species a series of fifty specimens, all 

 from Albuquerque, New Mexico, lies before me. Of these only two of 

 the males are so heavily marked with black as the figure, while all but two 

 of the females are darker, the majority tending towards a (but lacking the 

 humeral spot), while one is almost as dark as q. In this species, as in 

 pulchcllus, the females are the more heavily marked with black, but the 

 size of my specimens is so constant that no correlation can be traced 

 between size and colour. It may be worthy of remark, however, that the 

 specific pattern of coloration involves much less black than that of 

 C. ptclchellus, while the actual size of the insect averages much greater — 

 an indication of a tendency in large species in this genus to become light- 

 coloured as well as large individuals of some of the species. 



At / is shown a specimen of C. intermedins, which will illustrate the 

 pattern of coloration of the only specimen I possess. It differs from most 

 of its congeners in having pale legs and antennae, and inhabits the drier 

 portions of the southern plains in the same localities, and with the same 

 habits, as C. pulchcllus, though the range is probably much less extended. 



C. nitidicollis, Casey, is represented by figures m and n, and is found 

 in the neighborhood of Tucson, Arizona, and on the foothills of the 

 mountains near by. It will be noticed that the male shows very little 

 black, while the female is quite dark, almost exactly resembling fig. f of 

 C. pulchellus. Here we find the female, as usual, darker than the male. 



In the figures o and p, which show the markings of C. discoideus, a 

 red and black species, is noticed an extension anteriorly of the sutural 

 mark, which here reaches the base of the wing covers, with, in one case, 

 a corresponding increase of the humeral spots which have been spread 

 over the whole base of the elytra, and become confluent with the sutural 

 blotch. Both specimens are females, so no sexual comparisons can be 

 made, though the small specimen is the darker. My specimens are from 

 the high mountains of Colorado (Cockerell) and from Williams, Arizona, 

 the latter place at an altitude of between 6,000 and 7,000 feet. 



The results of some researches regarding melanism in insects have 

 lately been published by Mr. J. W. , Tutt, of London, England. He 

 believes that moisture is the chief excitant cause of melanism, and has 



