160 MEMOIRS ON THE COLEOPTERA 



short but narrowly rounded, very gradually formed lobe, the edges at 

 the sinuses with a few coarse foveiform punctures; scutellum small, but 

 little wider than long; elytra two and one-half times as long as the pro- 

 thorax and, near basal third, where they are feebly inflated, rather dis- 

 tinctly wider than the latter, the outline behind the inflation very ob- 

 tusely ogival, each with six unimpressed series of moderate but con- 

 spicuous, rather widely and unevenly spaced punctures, obsolete basally 

 and for a longer distance apically, the fifth series however attaining the 

 base; sterna and abdomen wholly impunctate. Length 3.7-4.2 mm.; 

 width 2.2-2.45 mm. Isthmus of Panama (Colon), Beaumont. 



This species is undoubtedly closely allied to pauper culus Lac., 

 from Colombia, but it is somewhat smaller and some of the state- 

 ments of Lacordaire do not agree very well, as for example, in de- 

 scribing the sides of the prothorax, the author says "un peu arrondi 

 sur les cotes anterieurs, " while here they are almost evenly rounded 

 throughout the length; it is also said that the elytral punctures are 

 "peu marques," while here they are conspicuous, and that the 

 series "n'arrivent pas tout-a-fait jusqu'a 1'extremite," while here 

 they are not traceable in apical two-fifths of the length. The figure 

 given by Mr. Gorham is very misleading, as the artist has drawn 

 the large cells showing through the elytra, which however are not 

 distinct in vernix, as punctures, the true punctures being omitted. 

 The prothorax here is less transverse than in the specimen illustrated 

 in the "Biologia," and the apical sinus is very deep. 



Tritoma Fabr. 



As stated by Gorham, it is very difficult to define this genus 

 unequivocally, though the same might be said of many genera of 

 Erotylidse when structural characters of the mouth are relied upon. 

 In fact, as in many other parts of the Coleoptera, it is the general 

 habitus of the species which, after all, forms the surest criterion 

 in the limitation of genera, unless there be some radical structural 

 feature that interferes, such as the coarsely faceted eyes in preventing 

 an assignment of Ischyrus nigrans Cr. (Tritoma brunnea Lac.) to 

 Tritoma, the outward resemblance here being very marked. Tri- 

 toma is essentially a subarctic genus and the species are rather 

 numerous; our own are systematically defined by Crotch (Tr. Am. 

 Ent. Soc., 1873, p. 355), although he has made a few errors, and only 

 one species, tenebrosa Fall, has been described since; this is entirely 

 black, somewhat as in unicolor but narrower or less oval in form and 



