STArHYLINIDAE. 67 



conical, and prominent, and the posterior ones are conical and 

 prominent. The antenna? are straight, with the last three joints 

 larger than the preceding ; the insertion varies in the different 

 groups ; the trochanters are simple. The second ventral segment 

 is marked with two short ridges. The first joint of the maxillary 

 palpi is nearly as long as the second. 



Three groups, according to the insertion of the antennae, are 

 obvious : — 



Antennae 11-jointed, inserted on the front, between the large eyes. Steni. 

 Antemue 11-jointed, inserted on the front, in front of the moderate eyes. 



Ec.estueti. 

 Antenna? 10-jointed, inserted under the lateral margin of the front. 



Megalopes. 



Group I.— Steni. 



The eyes are very large and prominent in this group, so that 

 the head resembles that of Ciciudela; the antenna? are inserted 

 upon the front, between the eyes. The labrum is entire, and 

 rounded anteriorly. The tarsi have five distinct joints. 



Two genera, both represeuted in our fauna, are known: — 



Paraglossae connate, indistinct (body finely punctured). Dianotts. 



Paraglossa? dilated, rounded (body coarsely punctured). Stenus. 



The species of this tribe are found running on mud near water ; 

 those of Stenus are numerous, and, according as the abdomen is 

 margined or not, and the fourth tarsal joint simple or bilobed, 

 may be arranged in natural groups ; the genus is represented on 

 both sides of the continent. Of Dianous but two species are 

 known ; one is European, the other was found by me on the 

 southern shore of Lake Superior. 



The ligula is attached by a loose membrane in Stenus, and 

 after death is frequently protruded to a distance equal to half the 

 length of the body. 



Group II.— Euaestheti. 



But two genera, containing only a few species, compose this 

 group. They are insects of very small size, found on flowers. 



The eyes are moderate in size, and but slightly prominent; 

 the antennas are inserted on the front, before the eyes, at the base 

 of the labrum, which is denticulate anteriorly. The tarsi are 

 4-jointed. 



(tody punctured. Ec/esthetus. 



Body smooth. Edaphiis. 



