400 Mr. H. W. Bates on the Longicorn Coleoptera 
that species. I have not seen either form in collections from 
other parts of South America. 
Genus PiatysterNvs (Dej.), Blanch. 
Blanchard, Histoire des Insectes, ii. 156. 
The few words given by Blanchard as generic characters, in 
the place above quoted, have little or no meaning; the genus, 
however, is well known to entomologists from the figure given 
by Olivier of the only described species. It is a singular form 
of Lamiaire, partaking of the characters of Stetrastoma and the 
Anisocerinee—two widely different groups. The shape ef the 
thorax, the closed acetabular sutures, and the direction of the 
centro-basal ridges of the elytra show a near affinity with the 
Steirastomata; whilst the form and smoothness of the muzzle, 
the broadly rounded apices of the elytra, and the depression of 
the fore edge of the metasternum are so many points of resem- 
blance to the Anisocerine. The lateral prominences of the 
thorax are not simple, but bicuspid, the anterior cusp, however, 
being very much smaller than the posterior one. The antennz 
are slender, one-fourth shorter than the body, and the eleventh 
joint, as in most of the Anisocerinz, is much shorter than the 
tenth. 
Platysternus hebreus, Fabricius. 
Cerambyx hebreus, Fabr. Mant. Ins. i. 131. 
, Oliv. Ent. iv. p. 62, t. 15. f. 106. 
I met with this rare and magnificent insect only at Caripi, 
near Para. It was there found in some numbers, gnawing the 
bark of living Guaritba trees—a lofty tree of the order Legu- 
minose, whose bark is thick, smooth, and friable, and much fre- 
quented by bark-feeding insects, especially Curculionides of the 
group Cryptorhynchini. Cicindelide of the rare genus Jresia 
are sometimes seen on the same tree, coursing over the trunk 
and preying upon the vegetable feeders; in fact, I never met 
with Jresie except on Guaritba trees. The large Cratosomi 
sometimes abound, and gnaw large holes in the bark. These 
insects do not seem to breed in the wood of the standing trees, 
He merely to resort to them for the purpose of gnawing the 
ark. 
I have seen a second and undescribed species of Platysternus 
in the collection of Count Mniszech, at Paris. 
Genus Potyruarpuis, Serv. 
Serville, Ann. Soc. Ent. Fr. iv. 26. 
From the seemingly capricious way in which the various parts 
of structure that, in other Coleoptera, furnish signs of affinity 
