COEEOPTERA. 6 



the northern regions are the true home of the Stenini, and here 

 they exist in prodigious variety and numbers. As we go south the 

 species and individuals become much less numerous, until finally, in 

 the West India Islands, there is, according to Mr. Schwarz, but one 

 species at present known. This rule does not, however, apply strictly 

 throughout, and there are many species described from Mexico and 

 tropical South America, but in these cases, if I am correctly informed, 

 they are generally found in the mountainous districts, and consequently 

 in a climate more temperate in its nature than that of the surround- 

 ing regions. 



The species of the Atlantic seaboard are generally distinct from 

 those inhabiting the great internal lake region, and both these in turn 

 differ, in general, from those of the Pacific coast and Alaska. The 

 species from California and Nevada have, as a group, a somewhat 

 different appearance from the Eastern species, being generally robust 

 and more depressed, with smaller heads and longer elytra. On the 

 other hand, a few forms, asjuno (Fab.), semicolon Lee, and stygicus 

 Say, have a very wide range of distribution, and several are known 

 to be quite cosmopolitan. 



It will be seen, on comparing our fauna in this group with that of 

 Europe, that they differ decidedly in the relative proportions of species 

 with simple tarsi and those in which the. fourth joint is bilobed, or, 

 according to the divisions here adopted, in the genera Stenus and 

 Areas respectively. 



Philadelphia, Aug. 10, 1^4. 



STENINI. 



General Characters. 



Head variable in size, usually large and relatively much wider 

 than long. Eyes large, strongly convex, occupying nearly the entire 

 side of the head, sometimes sparsely and minutely setose, always 

 finely reticulated ; lenses not perceptibly convex. Labrum large, 

 corneous, strongly, evenly and broadly arcuate anteriorly ; entire 

 surface rapidly declivous, conical. Interocular surface variable in 

 form, generally more or less depressed, sometimes, however, feebly 

 convex ; generally having two longitudinal sulcations, which are 

 slightly convergent anteriorly, the intermediate surface being more 

 or less convex and prominent ; rarely the sulcations and longitudinal 



