254 THE CANADIAN ENTOMOLOGIST. 



apparently longer legs, the comparison being made from the male in each 

 instance. 



Omus, Esch. 

 In this genus it is impossible to say that any really serious work has 

 ever been attempted, and time and material are still insufficient to bring 

 the present study under any such purview. It may be expedient, how- 

 ever, to correct at this opportunity certain impressions, possibly derivable 

 from the recent publications of Dr. W. Horn, of Berlin, who has left the 

 subject in such a condition of uncertainty, that few apparently consider it 

 worth while to give much attention to the taxonomy of the genus from 

 any point of view. This author has placed practically all the Califomian 

 forms under a single specific heading, granting to none of them any higher 

 status than the subspecies. The absurdity of this decision can best be 

 demonstrated by means of the accompanying outlines (Fig. 7), drawn from 



the protruded male generative 

 organ of a number of species, 

 which, as can be readily per- 

 ceived, differ so much in several 

 cases as in all probability to 

 prohibit copulatory union of 

 the sexes, — the best possible 

 proof of specific isolation. 



FlG. 7. — 1. Copulatory spicule in Omus Tu/arensis ; 



2, same in o. Dunni : ;,. same in o. parvicolUs; 4. same These drawings are not in any 



in O. lugubr/s ; 5, sa;ne in O. elongatHS. ' 



case foreshortened, but are the 

 accurately delineated outlines as seen in a direction truly perpendicular 

 to the plane of the lateral face of the organ. In the case of tlottgatus 

 the intromittent spicule is so aberrant that I carefully looked for some 

 evidence of accidental deformation, but could find none ; the substance of 

 the spicule is densely chitinized, and, viewed under higher power, betrays 

 no indication of injury ; but the divergence from the usual conformation 

 is so radical, in a species not notably aberrant otherwise, that I do not 

 desire to maintain definitely that we may not be dealing here with a most 

 remarkable deformity in the unique type of the species. 



In regard to sculpture of the elytra, Dr. W. Horn states that it is 

 without weight in distinguishing species, referring particularly to the 

 extreme case of puncti/rons and confluens ; but, on the other hand, Dr. G. 

 H. Horn states, in the remarks under his description of LeContei : " The 

 elytral sculpture is remarkably uniform in all the specimens of Omus that 



