150 NORTH AMERICAN 



Habitat in insula Kadjak rarissime ; D. Holmberg. 

 Individuis minoribus St. nigrituli Gyllenb. magnitudine aequalis, 

 sed punctura parciore et fortiore omnino diversus (" Maklin") 



AREUS n. sen. 



ux_~ 



O -*$** 



In the course of remarks made in the first part of the present 

 memoir, I have given most of the reasons, which appear to me 

 sufficient for the generic separation of those Stenini, in which the 

 fourth tarsal joint is distinctly bilobed. Species in which these lobes 

 are not apparent, and in which the fourth joints are merely swollen, 

 or slightly emarginate at tip, are excluded. 



On the plate the maxillae of two representative species in the 

 genera Stenus and Areus are figured, and it will be seen that they 

 exhibit differences which may be considered as, in a measure, vali- 

 dating the separation, although it is probable that there are forms 

 intermediate ; I have not had time to fully consider this rather in- 

 teresting investigation. As before remarked, there are many more 

 aberrant forms in Areus than in Stenus; those species in which both 

 the males and females possess good sexual characters, abound^in the 

 former and are quite rare in the latter, and, although generally 

 throughout the group, the males are smaller and more slender in 

 form than the females, there are many species of Areus in which the 

 reverse of this is the case. 



In many closely allied species the tarsal claws are variously, and 

 often considerably modified in shape. These aberrant forms are 

 figured on the plate, but are not employed for purposes of classifica- 

 tion, owing to the difficulty of viewing them to advantage. Some of 

 the species resemble each other very closely in general appearance, 

 and will require very careful attention to the descriptions in order to 

 be accurately determined ; doubtless a few of them still remain un- 

 described. The European species tarsalis Ljungh, plantaris Erichs., 

 and cicindeloides Schall., are closely allied to several of these, but are 

 quite distinct; the points of distinction will be given under the 

 corresponding descriptions. 



The main subdivisions of the genus are those generally followed, 

 and are very natural, there being no .species at present known within 

 our faunal limits, which can give rise to much doubt as to its proper 

 position. The secondary characters of importance are few in num- 

 ber, very distinct, and easily recognizable ; the tertiary characters, 

 however, are very feeble, and, as they are forced to serve for the 



