AMERICAN ENTOMOLOGY. 107 



retracted, so that no remnant of them remains in view. The 

 cocardes are three-lobed bodies, of a vivid red color, and vesicu- 

 lar consistence, situated one on each side near the anterior 

 angles of the thorax, and another on each side of the base of the 

 abdomen. Their uses are altogether unknown, but we cannot 

 suppose them to be of primary importance, since one, and indeed 

 all of them have been cut off without diminishing the agility of 

 the insect, or subjecting it to any apparent inconvenience. Like 

 the retractile cervical appendage of the larvas of Papiliones, it 

 may possibly serve to repel their enemies. Olivier supposes 

 that the larvae of the Malachius live in wood. Latreille informs 

 us that in some of the species one sex has an appendice at the 

 tip of each elytrum, in the shape of a hook, which is seized by 

 the mandibles of the opposite sex in order to arrest the fugitive. 



Malachius BIPUNCTATUS. — Specific character. Thorax ru- 

 fous, with two remote black spots ; elytra blue ; abdomen sangui- 

 neous. 



M. bipunctatus nobis, Journ. Acad. Nat. Sci. vol. iii. p. 185. 



Desc. Head black, with a slight greenish tinge ; all before a 

 line drawn between the anterior canthi of the eyes, including the 

 antennas, yellow; mandibles and terminal joints of the palpi 

 black ; thorax yellowish-rufous, with two small remote, rounded 

 black dots; posterior submargin somewhat indented: elytra blue 

 or greenish : pectus rufous : postpectus and feet black : abdomen 

 sanguineous. 



Obs. This fine species is an inhabitant of the Arkansaw re- 

 gion near the Rocky Mountains, where I captured two speci- 

 mens. In magnitude it exceeds any other North American spe- 

 cies yet known. The second joint of the antennas in the male is 

 dilated and irregular. 



The lowest figure of the plate. 



[Belongs to the genus Collops Er. — Lec.] 



Malachius tricolor. — Specific character. Head, postpectus. 

 and feet black ; labrum and thorax rufous ; abdomen rufo-testa- 

 ceous. 



M. tricolor nobis, Jour. Acad. Nat. Sci. vol. iii. p. 182. 



Desc. Head black; labrum, clypeus on its anterior margin ami 

 palpi at base, pale rufous : antennas pale rufous, dusky at tip : 

 thorax transverse, nearly oval, rather short, rufous, immaculate : 



