122 Journal New York Entomological Society. [Vol. xxi. 



vergent apically. The apices of the posterior coxal wings are strongly 

 angulate, more so than in edcntuliis, and the hind femora ringed 

 with yellow before the knees. The joints of the front and middle 

 tarsi in the males are very little modified, yet sufificiently so to at once 

 separate them from the females. 



Peltodytes edentulus Leconte. 



This species is so well known by the black collar on the base of 

 head that comment is scarcely necessary. I may state, however, that 

 the species has no subhumeral spot, or dash of black ; that the apices 

 of elytra are decidedly sulcate, more so than in 12-punctafus, and 

 while the apices of the hind coxal plates are evidently angulate they 

 are not so strongly so as in the above. It is one of the three species 

 with the yellow band before the knees on the posterior femora. 



The tarsal joints of the front and middle legs are thickened and 

 slightly produced at apices in the males. 



I have seen specimens with the head so much retracted as to com- 

 pletely conceal the black collar and, for the moment, disconcert one. 



I have specimens from as far north as Treesbank and Winnipeg, 

 Manitoba, collected by Mr. J. B. Wallis. 



While I have indicated groups into which the species of Haliplus 

 more or less naturally fall, and have given comparative characters by 

 which to separate those in the different groups, I have not under- 

 taken to make a table as I have not recognized three of Mr. Mathe- 

 son's species. 



A table of the species of Peltodytes follows. 



Posterior femora entirely black or brown i. 



Posterior femora black, ringed with yellow before the knees 2. 



Posterior femora pale, knees only darker 3. 



I. Elytra without subhumeral spot, or dash of black 4.- 



Elytra with a subhumeral spot, or dash of black 5. 



4. Elytra without distinct callosity, or tubercle 6. 



Elytra with a distinct callosity callosvs. 



6. Apex of prosternal process distinctly margined 7. 



Apex of prosternal process not distinctly margined simplex. 



7. Fourth stria incomplete, interrupted medianly 8. 



Fourth stria complete dispersus. 



8. Median spots coalescent on suture forming a black blotch mnticus. 



Median spots free, not coalescent on suture sexniaculatus. 



5. Sutural margin uneven, noticeably wider basally than apically 9. 



Sutural margin even, not wider basally than apically festivus. 



