DIAPERINI NORTH OF MEXICO — TRIPLEHORN 433 



illary palpus elongate oval, truncate apically; antennae clavate, 

 extending but slightly beyond pronotal base, basal segment thick, 

 segments 2 to 4 more slender, segments 5 to 10 slightly transverse, 

 becoming increasingly larger, apical segment large and elliptical. 

 Pronotum with lateral margins almost straight, broadly expanded and 

 reflected, apical margin deeply emarginate, angles acute and promi- 

 nent; base straight or slightly rounded, angles sharply obtuse. Elytra 

 punctate striate, strongly inflated near lateral margins, particularly 

 at base, lateral margins rather broadly expanded and reflected, hum- 

 eral angles prominent, smoothly continuous with expanded portion of 

 pronotal margin. Prosternal process broad and spatulate, not pro- 

 longed caudally, widely separating front coxae, mesosternum short, 

 flat, broadly U-shaped, widely separating middle coxae, epipleura 

 broad basallj^, gradually narrowing toward apex, abbreviated near 

 terminal suture of abdominal sternites; first abdominal sternite broad 

 and truncate between hijidcoxae, which are widely separated; legs 

 all moderately slender, basal and apical segments of hindtarsi long and 

 subequal, segments two and three very short and subequal. Male 

 aedeagus (pi. 3, figs. 19, 20) with apical sclerite truncate at base 

 dorsally. 



The small, shallowly impressed eyes, the stout clavate antennae, 

 the broad spatidate prosternal process, the broad truncate base of 

 the first abdominal sternite between the hindcoxae, the broadly 

 expanded and reflected lateral elytral margins with prominent hu- 

 meral angles, and the widely separated coxae of all three pairs of 

 legs serve to separate Scaphide?na from all other genera of Diaperini. 

 Lacordaire (1859) considered this genus to be intermediate between 

 Neomida and Platydema. Seidlitz (1894) pointed out that in general 

 habitus, Scaphidema appears more similar to Platydema, but that 

 because of the flattened mesosternum, it is in reality more closely 

 related to Neomida. Actually, these other two genera seem to be 

 more closely related, one to the other, than either of them are to 

 Scaphidema. Of the two, its closer affinities seem to lie with Platy- 

 dema, although even this relationship is not particularly close. 



Seven species of Scaphidema are known in the world fauna. Four 

 were described from Japan, one from China, one from Europe, and 

 one from North America. The latter two are the only ones available 

 during the present study. 



The European S. metallic um (Fabricius), type of the genus, has 

 been well studied. Gebien (1940) lists four synonyms and two vari- 

 etal names under this species, and the immatm-e stages have been 

 described and figured a number of times (Westwood, 1839, p. 314, 

 fig. 37; Schi0dte, 1879, p. 552, tab. 9, figs. 10-16; Seidlitz, 1898, pp. 

 212, 215; Eeitter, 1911a, p. 339, fig. 121). 



