NATURAL SCIENCES OF PHILADELPHIA. 87 



stilus planis, vix rujrulosis biseriatim subtiliter punctulatis, subtus subtiliter 

 punctulata, Lor.gr. '35. 



Southern and Western States; Dr. Le Conte. Closely allied to the preceding 

 species. Differing in the -much more transverse thorax, and the flat scarcely 

 rugulose interstrial spaces. 



18. T. b i m a c u 1 a t a, nigro aenea, subnitida modice depressa, capite 

 thoraceqae confertim puncUilatis hoc transverso, lateribus rotundatis, nuirgine 

 vix reflexo, angulis posticis parvis obtusis, basi rotundato, elytris elongatc- 

 ovalibus, macula flava ante medium, basi vix emarginatis, versus bumeros im- 

 pressis, striis punctatis, interstitiis modice convexis, valde rugulosis, biseriatim 

 subtiliter punctulatis, gulaantice subtiliter punctulata, postice biseriatim trans- 

 verse plicata. Long. -20. 



T. bimaculata, Mels. , Proc. Acad. ii. 



Middle States, rare : Southern States common. May be readily distinguished 

 by the subtransverse thorax with rounded sides and the brassy refulgence of 

 the elytra, which have an irregularly shaped yellow spot, slightly in advance 

 of the middle. 



19. T. o b s c u r a, rufo picea, subnitida, modice depressa, capite thoraceque 

 parce punctatis, hoc transverso, lattribus rotundatis, margine modice reflexo, 

 antice latiore postice vix angustaio, angulis postice parvis vix acutis, basi mo- 

 dice rotundato, elytris oblongo-ovalibus, basi vix emarginatis, humeris rectis, 

 stiiis punctatis valde impressis, interstitiis modice convexis, rugulosis, biseria- 

 tim subtiliter punctulatis, abdomine prosternoque parce subtiliter punctulatis, 

 gula antice confertim punctulata, postice modice plicata. Long. -20. 



Illinois ; two specimens, Dr. Le Conte. Resembbs the bimaculata Mels. 

 The thorax is less transverse and sides less rounded, the punctures are coarser 

 and less closely placed. The interstrial spaces are much less elevated and ru- 

 gulose. 



20. T. rugosipennis, rufo-picea, modice depressa, capite thoraceque, 

 confertim punctatis, hoc transverso, lateribus rotundatis, postice vix angustato, 

 margine vix reflexo, angulis posticis obtusis parvis, basi modice rotundato, 

 elytris oblongo-ovalibus, basi emarginatis, versus humeros impressis, striis 

 punctatis, interstitiis convexis valde rugulosis, biseriatim subtiliter punctulatis, 

 abdomine prosternoque parce punctatis, gula antice punctulata, postice subpli- 

 cata. Long. -17. 



One specimen, Pennsylvania; Dr. Le Conte. This is the smallest known 

 North American species. Its form is more convex, and the sides of tie thorix 

 are more narrowed than in the other species of this group. The interstrial 

 spaces of the elytra are very convex and rugulo-e, the intermediate rows of 

 punctures are quite large, giving to the elytra a roughened appearance not seen, 

 in any other member of tne genus. 



B 4. 



21. T. obtusa, ferruginea, subnitida, valde depressa, capite thoraceque 

 conb-rtim subtiliter punctulatis, noc lateribus valde rotundatis, antice latiore, 

 postice angustato, margine vix reflexo, basi rotundato, medio emarginato, an- 

 gulis parvis minutis, vix prominulis, elytris ob'ongis, basi rectis, striis punc- 

 tatis, interstitiis planis parce rugulosis, biseriatim subtiliter punctulatis, abdo- 

 mine gula prost* rnoque parce subtiliter punctulatis. Long. -27. 



Two specimens, Pennsylvania, H., Dist. Columbia; TJike. 



This species may be readily known from any other by its more elongated de- 

 pressed form, the postetior angles of the thorax small, scarcely' evident, and 

 sides much rounded. The width of the base equals about one half the width 

 anteriorly. Its form is more depressed than any other Trogosita. the lateral 

 view being almost linear. 



1862.J 



