DIAPERINI NORTH OF MEXICO — TRIPLEHORN 359 



eus and labrum. In all genera which have been studied during the 

 present survey, this structure has been distinctly present and may be 

 used at least for all New World genera of Diaperini. Gebien (1925) 

 reported that it is absent in Labidocera Gebien, from the Indo-Malayan 

 region and in Menimus Sharp, from New Zealand. Since both of 

 these genera have subsequently been removed from the Diaperini 

 (Gebien, 1940), it is reasonable to assume that all members of the 

 tribe as it is currently understood have the membranous band present. 



It is the presence of this membranous band which strongly suggests 

 that the Phaleriini should be united with the Diaperini. In general 

 habitus and in the form of the male aedeagus, species of Phaleria are 

 remarkably similar to typical species of Platydema. Indeed, many 

 specimens of the former genus were sent along with Diaperini for 

 identification and in one very famous collection, specimens of Phaleria 

 picipes LeConte, determmed by a distinguished coleopterist as Platy- 

 dema laevipes Haldeman, have stood unchallenged for half a century. 



The most constant difference between the two tribes, and the only 

 conceivable reason for retaining them as distinct, is the greatly ex- 

 panded front tibiae and spiny legs in species of Phaleria and related 

 genera. The broad front tibiae are not entirely absent in the Dia- 

 perini; several of the dark, chestnut-colored species of Neomida from 

 South America (e.g., A'', castanea Bates and A^. hoffmannseggi Laporte 

 and Brulle) have these members fully as broadly expanded as in many 

 of the Phaleriini. 



A critical study of the relationships between the Diaperini and 

 Phaleriini must be deferred until later, but it seems that there 

 is little justification in retaining them as two distinct tribes. 



In all species of North American Diaperini, there is a finely cren- 

 ulate, sharp margin on the outer face of the hindtibiae. This char- 

 acter was discovered by Gebien (1925), who used it as the decisive 

 one in doubtful cases. On this basis, he removed Basanopsis from 

 the Diaperini and transferred it to the Ulomini. 



The tribal limits therefore may be stated at this time as consisting 

 of two well-defined characters: (1) the finely crenulate ridges of the 

 hindtibiae and (2) the membranous band between labrum and clypeus. 



Based on these criteria, a number of taxa, formerly included in 

 this tribe, must be placed elsewhere. In the North American fauna, 

 the following changes must be made: Metaclisa Jacquelin du Val 

 should be placed in the tribe Cnodalonini, and Corticeus Piller and 

 Mitterpacher (=Hypophloeus Fabricius) should be placed in 

 Ulomini. These two transfers have already been made by Gebien 

 (1940) and appear quite sound. 



The species described by Horn (1874) as Scaphidema pictum has been 

 transferred to the Phaleriini, where it now stands under the name 

 Phaleromela variegata Triplehorn. The biological and nomenclatorial 



