9T 



character is common to all the females of the same group 

 uith Action, and the former character is most probably as 

 universal *. 



Having once seen a female variety oi Actcson with smooth 

 elytra, I was induced to suppose that there were probably 

 two species that had been confounded under that name ; 

 and soon after observing a male with crenated elytra, this 

 opinion was strengthened. 



, ^\llen I mentioned my suspicions on the subject to 

 Mr. MacLeay, he assured me that he had seen similar vari- 

 eties of the male ; and that on examining a sufficient num- 

 ber of specimens, I should be convinced that they were but 

 varieties of one species : I did so ; and was nearly induced 

 to adopt the opinion of this excellent entomologist, when 

 I discovered sufficient characters to distincruish them from 



o 



each other. 



Before pointing out the marks by which these species are 

 distinguished from each other, it may not be improper to 

 mention the most striking characters of the group to which 

 they belong. 



Clypeiis utrinque antice unidentatus. Verte.v tuberculatus 

 aut cornutus. Mandlbuhe valde prominulae externe va- 

 lide bidentata^ ; dcntibus longitudine tequalibus in his, 

 ina^qualibus in illis ; cxteriore in omnibus crassiore. 



* The feinak* Dytici have their elytra deeply sulcated, but they some- 

 times occur with the sulci nearly obsolete. Nine years since I found 

 |his variety, and having discovered the Linnx^an error with regard 

 to the sexes of D. marginalis, which he described as species, was 

 very much perplexed. The same variety was observed by Kirby, who 

 regarded it as a neuter ; and by Gyllenhall, who rather suspected it 

 to be a male. Bonelli, however, lately sent me a similar variety from 

 Piedmont, saying that he had met with three specimens, which on dis- 

 section proved to be females. 



VOL. III. O 



