•22S LECONTE— SYNOPSIS OF PTEROSTICHUS. 



2. Striis marginalibus non approximatis. 



d. Thoraee lotuadato-cordato, postice unistriato. . . . . . . . Sp. 13 — 17. 



e. Thoraee cordate, postice utrinque bistriato. ....... Sp. 18 — 29. 



a. 



The species of this group are somewhat oblong insects, usually of a dull black 

 color, with little lustre. The thorax is quadrate, rounded on the sides, with the pos- 

 terior angles obtuse, not rounded, and not prominent; the basal impression is very 

 distinctly double, with a slight ridge at the margin ; the posterior transverse impres- 

 sion is so deep on each side as to appear like a third basal impression ; the anterior 

 transverse line is deep. The elytra are marked with entire but not deep strise, which 

 are distinctly punctured ; the eighth and ninth are very closely approximated, being 

 scarcely as far apart as the diameter of the ocellate punctures which are between 

 them; the scutellar stria is usually an oblong point. The last ventral segment of the 

 males is widely impressed ; in the first four species this impression is divided by a 

 longitudinal elevation, in E. conviva, it is single and undivided. 



1. E. Engelniani, thoraee transverso, distinctius marginato, margine versus basin latius reflexo, eljtris 



profundiusstriato-punctatis, interstitiis modice convexis. Long. '92. 

 Texas: collected by Lindheimer, and given me by Dr. Engelman. It resembles 

 very closely E. americanus, but is larger, the thorax is more broadly margined on 

 the sides posteriorly, and the margin is reflexed. The elytra are more deeply striate, 

 and the interstices are tolerably convex. 



2. F, sig Hiatus, thoraee subtransverso, tenuius reflexo-margtiiato, elytris striis profande punctatis 



interstitiis planiuseulis. Long. -67. 

 Fcronia sigillata Say. Trans. Am. Phil. Soc. 2, 42. 

 Feronia vidua Dej. Sp. Gen. 3, 278. 



Middle States and Missouri Territory. The margin of the thorax is reflexed as in 

 the preceding, but is scarcely wider behind than before. 



8. E. seximpressus, thoraee subtransverso, postice latius reflexo-marginato, elytris striis profunde 

 punctatis interstitiis planis. Long. -58 — 62. 

 Feronia seximpressa Lee. An. Lye. 4, 350. 



Missouri Territory, near Long's Peak. This species nearly resembles the preced- 

 ing, but the reflexed margin of the thorax is wider posteriorly than even in E. Engel- 

 mani. 



4, E. americanus, thoraee antrorsum subangustato tenuiter marginato, margine non reflexo, elytris 

 striato-punctatis, interstitiis fere planis. Long. -8. 

 Feronia (Abax) americana Dej. Sp Gen. 3, 392. 



South Carolina and Georgia, not common. Dejean failed to recognize the relation 

 between this species and E. sigillatus, from which it diff"ers only by having the thorax 

 a little narrowed in front, a little less rounded on the sides, with the margin very 

 narrow and not reflexed. 



