AMERICAN PHILOSOPHICAL SOCIETY. 519 



margin; elytra paler than the body, striae profoundly punctured, 

 punctures color of th« elytra, suture, base, tip and six spots on 

 each elytron deep black, spots placed 1, 1, 2, 1, 1, the penulti- 

 mate one joining the suture, suture at the centre dilated into a 

 spot. 



GYRINUS Linn. 



Antennae shorter than the head, second joint with a lateral 

 process ; eyes apparently four ; two posterior pairs of feet dilated 

 very much compressed. 



1. Gr. AMERiCANUS. — Blackish bronze, beneath piceous ; elytra 

 smooth, slightly sinuate at tip. 



Length nine-twentieths of an inch, breadth more than one- 

 fourth of an inch. 



Gyrinus americanus, Isvis, ater opacus, pedibus quatuor posticis testa- 

 ceis. Fabr. Syst. Eleuth. 1, 275. 



G. americanus, bronze ; pattes ferrugineuses ; eljtres simples, presque 

 striees. Oliv. Ent. 3, No. 41, p. 12, pi. 1, fig. 5. 



G. americanus Dr. Forsberg, Trans. Upsal Society. 



Body oblong, subovate, blackish, slightly tinged with bronze 

 or purplish, beneath piceous ; head, labrum deeply ciliated with 

 white hair ; thorax impunctured, scutel none ; elytra with very 

 minute obsolete, distant punctures, disk plain, each side with 

 four or five obsolete striae, tip distinctly and very obtusely 

 sinuated, a projecting angle at the sutural tip ; poststernum with 

 distant profound punctui'es before ; feet testaceous, anterior pair 

 rufous and destitute of a femoral spine. 



A very common insect. When caught, a lactescent fluid [108] 

 is secreted from the anal segment, that diffuses a strong odor 

 very similar to that of the flowers of the Calycantlias. 



2. Gr. EMARGINATUS. — Blackish-bronze, beneath blackish ; 

 elytra smooth, each simply rounded at tip. 



Length nine-twentieths to eleven-twentieths of an inch. 



Body blackish-green, slightly bronzed ; beneath piceous black 

 or fuliginous ; head blackish-green \ labrum at tip and antennae 

 at base ciliated with white hairs ; thorax impunctured ; scutel 

 none ; elytra with veiy minute, obsolete, distant punctures, striae 

 seven ^or eight, more distinct in the % , obsolete, each elytron 

 1823.] 



