STAPIIYLINIDAE. 97 



4. Middle coxae distant. Leptacinus. 



Middle coxae contiguous. Metaponcus. 



S.Tliorax oblong, elytra with tlie sutural stria obsolete. Othius. 



Thorax oblong, elytra with a deep sutural stria. Baptolinus. 



Thorax narrowed in front, elytra with a deep sutural stria. Diochus. 



Tribe III.— STElVIiM. 



Ill this tribe the prothoracic spiracles are concealed by the 

 iiiflexed portion of tlie pronotura ; the anterior co.\a3 are small, 

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

 prominent. The antenna? are inserted upon the front, straight, 

 11-jointed with the last three joints larg-er than the preceding; 

 the trochanters are simple. The second ventral segment is 

 marked with two short ridges. The first joint of the ma.xillarv 

 ])alpi is nearly as long as the second, and the 4th is obsolete. 

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

 the head resembles that of Cicindela. The labrum is entire, and 

 rounded anteriorly. The tarsi have five distinct joints. 



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



Paraglossae connate, indistinct. Dianous. 



Paraglossae dilated, rounded. Stenus. 



The sjiecies of this tribe are found running on nuid 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, and occurs also at Lake Superior, the 

 other is found from New Hampshire to British Columbia. 



The lignla 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. Eugesthetus and Megalops have been asso- 

 ciated in this tribe, but in our opinion improperly ; tli(! former 

 will in this work be found in P»derini, the latter in O.xytelini, 

 where it was first placed by Erichson. 



Tribe IV.— P^DERII¥I. 



In this tribe the prothoracic spiracles are invisible, being 

 covered by the sides of the pronotum; the space behind the co.xai 

 1 



