DIAPERINI NORTH OF MEXICO — TRIPLEHORN 397 



studied from scattered localities iii ]\Iexico, Honduras, and Costa Rica 

 fit into the clinal concept quite well. 



Platydema excavatum is most likely to be confused with P. teleops 

 and P. cyanescens. The vivid blue color of the latter species, com- 

 bined with the discontinuous variation in the ventral distance between 

 the eyes of this species and of specimens of P. excavatum from southern 

 localities, should be sufficient to distinguish it. 



Except for color, P. teleops is even more distmct than P. cyanes- 

 cens, the distance separating the eyes ventrally reaching its height 

 (3.2-4.2 times the longer axis of one eye) in P. teleops. Other char- 

 acters, which unfortunately presuppose a familiarity with P. excavatum 

 and hence are relative in nature, include the more narrowly elongate 

 body, the more shining lustre, the flatter pronotum and elytral 

 intervals, and the finer punctation of the entire dorsum. 



Types. — Diaperis excavata Say. Not seen, presumably lost; type 

 locality, "Arkansa" [sic]. Platydema tuberculataljeL^povte and Brull6. 

 Not seen, type locality, Cuba. P. nigritum ^lotschoulsky. Not seen ; 

 specimens from Mississippi were said to compare with the type 

 (Kelejnikova, in litt.) present in UMMZ; type locality, "Nouvelle- 

 Orleans et a Atlanta." At the latitude of these two southern cities, 

 any shiny black Platydema with horns almost certainly is excavatum. 

 P. fraternum Chevrolat. Not seen and coidd not be found in Paris 

 Museum (M. Villiers, in litt.) ; type locality, "Santo Domingo." 

 Champion (1886) examined a "typical example from Santo Domingo" 

 which he proclaimed to be "merely a small P. excavatum." P. 

 parvulum Casey. Willets Point, Long Island, N.Y., USNM 46812. 

 The single specimen representing this species in the Casey collection 

 is a female, although the origmal discription specifies a male in which 

 "the frontal horns are rudimentary." The description is lengthy and 

 quite accurate, but the salient characters which are weighed most 

 heavily in the present paper are omitted, and as a result the descrip- 

 tion could apply to either P. excavatum or P. teleops. In a note at the 

 end of his paper Casey (1884, p. 195) states that "P/. parvulum is 

 perhaps a very small and singularly deformed specimen of excavatum, 

 and the name should therefore be entered as a synonym of that species 

 until future collecting can decide upon its true relationship." 



Horn (1885), without further comment, placed it in synonymy 

 with P. excavatum. In 1890, Casey (p. 485), without mention of 

 supplemental material, elaborated further on his original description 

 of P. parvulum and lists in the form of a key the differences between 

 it and P. excavatum. The differences to which he alludes simply do 

 not exist and "parvulum" may at best be regarded as a very small, 

 deformed, teneral specimen of excavatum, a course which Casey him- 

 self was almost willing to follow in 1884. Following are notes taken 



767-059—65— — 4 



