108 AMERICAN ENTOMOLOGY. 



Linn., of Europe, is a fifth species, wliicli, however, Fabricius 

 placed in his genus Gerris. 



The word Ploiaria, is of uncertain origin ; Mr. Duiueril sup- 

 poses it to have been derived from the Grreek name for a small 

 vessel, n\«*a/>/iv. (jiavicula?) 



Ploiariabrevipennis. — specific cJiaracter. Fuscous-rufous, 

 glabrous ; wings abbreviated ; feet near the knees annulated. 



Desc. Body fuscous, more or less tinged with sanguineous : 

 antennae very slender, with a white annulus at the tip of the 

 first joint : anterior tibire with the spines black at tip : nervures 

 of the wings brownish : intermediate and posterior feet with the 

 thighs near the tip, and tibiae near the base biannulate with 

 whitish : tergum beneath ^he wings bright sanguineous. 



Ohs. This is a very common insect, and is often found even in 

 the city of Philadelphia. It inhabits out-houses, where it may 

 be observed generally motionless on the walls. When disturbed, 

 it moves its body up and down on its legs, and at the same time 

 advances slowly forwards. 



The line denotes the natural size. 



MALACHIUS. Plate XLVIII. 



Generic character. Body furnished with cocardes : head re- 

 tracted to the eyes within the thorax : antennae ten-jointed, fili- 

 form, serrated ; mandibles emarginate : labium entire ; palpi fili- 

 form ', tarsi simple, nails with a tooth beneath ; elytra flexible. 



Ohs. Linnaeus referi'ed these insects to his genus Cantharis ; 

 from which his learned successor, Fabricius, separated them, 

 and constituted a group under the present name, derived from 

 the Greek word ^=tAax3?, which means soft, delicate, in allusion to 

 the consistence of the body. They difi"er from the genus Dasytes 

 Payk., in being less elongated, and furnished with the cocardes j 

 their antennae also are placed nearer together at base ; otherwise 

 the two genera are closely allied. 



These insects are frequent in some situations on flowers, the 

 nectareous juices of which they appear to extract, though it has 

 been asserted, but we know not upon what authority, that in ad- 

 dition to their liquid food they prey also upon insects. 



When alarmed for their safety, the cocardes are suddenly pro- 

 truded, and when reassured of security, these singular organs are 



