REVISION OF THE BUPRESTIDA OF THE UNITED STATES. 189 
GROUP I. 
This group is distinguished by the prosternum being obtuscly angulated on the sides 
behind the coxs, and then obtusely acuminate: the mentum is entirely corneous: the 
front is not lobed, the antennal cavities are variable in size: the antenne have the pores 
diffused on the lower portion of the sides, but varying greatly in the space they occupy. 
The mesosternum is closely connate with the metasternuim, and is broadly divided. The 
scutellum is small and rounded, sometimes not conspicuous: the tarsi are lobed beneath, 
and the first joint is elongated in two of our genera, and short in the third. 
Antenne sub carina majuscula insertee; mentum late rotundatum — - - Gyascutus. 
Antenne in foveis parvis insert; mentum late emarginatum - - Chalcophora. 
Antenne in foveis majusculis insertee; mentum late rotundatum - - Psiloptera. 
Gyascutus Lec. 
Antenne distantes sub carina obliqua elevata insertze, articulo Imo conico paulo crassiore, 2 et 3 cylindricis, 
4to trianeulari 3io haud breviore, margine inferiore poroso, 5—10 sensim paulo brevioribus, infra medium poro- 
sis; llmo apice lobato. Fossule antennales magne profunde. Labrum emarginatum. Mandibule valde 
obtuse; palpi maxillares haud dilatati. Mentum breve corneum antice late rotundatum. Prosternum lateribus 
postice angulatum, medio obtusum; mesosternum metasterno integro connatum, sutura obliqua, late divisum. Pe- 
des craciles, tarsi subtus lobati, postici plerisyue compressi articulo Imo elongato. 
This genus seems most related to Pelecopselaphus, which it resembles in form as well 
as in the narrow compressed posterior tarsi of some of the species: but it differs from that 
as from every other genus I have seen, by the elevated ridges above the antenne. 
The tip of the abdomen in both sexes has a transverse elevated line near the margin, 
which in the female is less distinct than in the male: in the latter the line is acute, and 
forms an acute tooth each side, thus causing the posterior outline to be distinctly sinuous, 
while in the female it is broadly subtruncate: the inferior anal plate is in the male pro- 
longed in the middle, forming an acute process, which, however, is usually concealed from 
view. The sides of the elytra are feebly serrate behind the middle. Our species form 
two groups; the antennal pores in the second are more numerous, covering nearly the 
whole of the sides of the articulations, and the basal joint of the posterior tarsi is less 
elongated, and less compressed. 
a. Epistoma late emarginatum: tarsi postici articulo 1mo sequentibus duobus equali. 
1. G. planicosta. Chalcophora planicosta Lec. Proceedings Acad. Nat. Sc., 1858, 66. Tab. XII. fig. 1. 
2. G. obliteratus. Chalcophora obliterata Lec. ibid. 
These two species were collected by Dr. Thos. H. Webb, on a journey from El] Paso to 
