358 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 117 



DiAPBRiNi LeConte, 1862, p. 236.— Horn, 1870, p. 378.— Redtenbacher, 1874, p. 

 104.— Seidlitz, 1875, p. 95; 1891, pp. 121, 131; 1894, p. 506.— LeConte and 

 Horn, 1883, p. 383.— Blatchley, 1910, p. 1260.— Reitter, 1911a, p. 338.— 

 Portevin, 1934, p. 23.— Gebien, 1939, p. 765.— Blackwelder, 1945, p. 527. 



DiAPERiNAE Gebien, 1911, p. 364; 1925, p. 134.— Leng, 1920, p. 233. 



Body usually oval and rounded, convex; wings well developed and 

 functional. Head usually retracted into thorax as far as eyes which 

 are emarginate anteriorly (except in Pentaphyllus); antennae with 

 outer segments thicker than basal ones, perfoliate, frequently forming 

 a distinct club; men turn small, gular peduncle distinct; genae ex- 

 panded to cover bases of mandibles which are short and bifid apically; 

 a distinct membranous band present between clypeus and labrum. 

 Pronotum transverse with distinct lateral marginal bead; basal mar- 

 gin bisinuate with a fovea on each side of middle. Elytra evenly 

 convex, never coarsely sculptured, usually punctato-striate, rarely 

 pubescent; epipleura narrow. Prosternum short; prosternal process 

 continuing posteriorly beyond front coxae; mesosternum more or 

 less grooved for reception of prosternal process (except in Liodema); 

 anterior coxae sub transverse; hindcoxae strongly and obliquely trans- 

 verse; anterior prolongation of basal abdominal sternite acute between 

 hmdcoxae; tibiae usually slender, spurs fine and short; hindtibiae 

 with finely crenulate ridges on outer margins; tarsi finely pubescent 

 beneath. 



Tribal limits. — ^The Diaperini have been treated a number of times 

 on a regional basis, but no recent attempts have been made to cor- 

 relate the information derived from a study of the world fauna. The 

 present paper can hardly lay claim to such a contribution, but at 

 least a serious attempt has been made to compare the North Ameri- 

 can components of the tribe with those from Central and South Amer- 

 ica. Enough northern European species were available to make 

 possible the mclusion of rather valuable, if scanty, information on 

 certain Holarctic genera (i.e., Scaphidema and Pentaphyllus). Gebien 

 has treated the West African (1920) and the Indo-Malayan (1925) 

 Diaperini and his general considerations and conclusions are supported 

 by and closely parallel those of the present study. 



This tribe is difficult to define both in determining its limits and in 

 its relation to other tribes within the subfamily Tenebrioninae. In 

 the past, the character variously expressed as "eyes more conspicuous 

 than sides of front" was used to separate the Diaperini from Phaleriini, 

 Ulomini, and related tribes. This character is misleading and utterly 

 worthless when one compares the small eyes of Pentaphyllus and 

 Scaphidema, both members of Diaperini, with those of most of the 

 species of Phaleria and with many genera of Ulomini. 



A very useful character which has been generally overlooked by 

 American workers is the shiny membranous band separating the clyp- 



