t consider lliem as the same ; in colour they may dif- 

 fer inconsiderably. 



2. G. ml tins, Hi/es reiiiform ; siijierior antennct 

 lon2;cr than the inferior ones, terminal joint ^vitliabo^t 

 ^velve articulations. 



Inhabits riviilcis and small fresh vrater streams. 



Cabinet of the Academy. 



Sadij whiiiftb^ with a fevr very pale fiilvons lateral 

 spol^ ; ejjes reniform, blackish, placed at fciie exterior 

 base 01 Uie superior antennie; superior antennct obvi- 

 ously longer than (he iaferior ones, seta sliort, attain-, 

 ing tlie \A]i of tlie second articulation of the term'tniil 

 joini, termioaj joint with about twelve articulations. 



Len^tli ihrec-lwentieths of an inch. 

 , Found in brooks under stones, and may be readilj^ 

 discovered by taking a stone out of the water, and in 

 specting its inferior surface. 



3. Ct. nuicronaius, E^/es irregularly rcniform^ 

 Ijlackish ; antemim subequal ; eighth, ninth, and iQiith 

 segments of the body niucronate above. 



JnliahitB the coast of the United States. 



Cabinet of the Academy. 



Antennm subequal, superior ones with about twen- 

 ty articulaiions in the terminal joint, seta attaining the 

 tip of the fourth articulation ; eyes somewhat reniform^ 

 fruncatc alcove, and forming an angle towards the up^ 

 per base of tjie antennie ; eighth, ninth, and tenth 

 joints of the bodj^ tprmin^tinj above in a strongs 



