Longicorn Coleoptera of Tropical America. 23 



of their mimetic disguises and the beautiful illustrations they 

 offer of the mode in which divergent modifications occur in 

 nature. For example, it is most instructive to observe, in forms 

 so very closely allied, that whilst some species have rudimentary 

 elytra, ample wings, and wasp-like bodies, or bee-like hind 

 tibiae (such as many of the species of Odontocera^ Charis, and 

 Tomopter us) ^oi\\QX& have elytra developed to the opposite 

 extreme, and, aided by colours and facies, become the mimetic 

 analogues of various Coleoptera — such as Oxylymma (re- 

 sembling Galerucid^), JEchnutes (resembling Lycidce), and 

 Erythroplatys (resembling Hispidas) . The lesson plainly taught 

 here, to those who believe in the origin of species by natural 

 variation and selection, is that the Rhinotragince have varied 

 in many directions, and that, a protective disguise of one kind 

 or other being necessary to the species, the variations have 

 been gradually drawn out in many different directions, ac- 

 cording as they resembled some object at hand which it was 

 advantageous to resemble. In the present stage it cannot be 

 said that the species are remarkable for variability in the parts 

 of their structure involved in the adaptations here mentioned : 

 but they are generally insects of great rarity ; and wherever a 

 large number of examples are at hand (e. g. Acyplioderes auru- 

 lentuSy femoratus, and hirtipeSy Ommata (Agaone) notabilis), 

 there is a large amount of variation in general form and colour. 

 If, however, we look at the differences between very closely 

 allied species tlie most abrupt changes are seen — such, for in- 

 stance, as those between Odontocerafdsciata {reseiTihlmg a wasp) 

 and 0. compi'essipes (resembling a bee, with pollen-gathering 

 apparatus to the hind tibiae). In fact the abruptness with 

 which important parts of structui-e change from species to 

 species renders the definition of genera impossible in this group ; 

 almost every species offers structural characters sufficient in 

 amount to render generic separation plausible. 



Genus Oxylymma, Pascoe. 

 Pascoe, Trans. Ent. Soc. ser. 2, v. p. 21 ; Lacord. Genera, vol. viii. p. 500. 



1. Oxylymma lepida^ Pascoe, I. c. p. 22, pi. ii. f. 3. 

 Ega, Amazons. 



2. Oxylymma telephorina^ Bates. 

 Oxylymma telephorina, Bates, Trans. Ent. Soc. 1870, p. 316, 

 Ega, Amazons. 



3. Oxylymma gihln'collis, n. sp. 

 0. flavo-testacea, erecte pilosa ; occipite, articulis antennarum 2<'-5"™ 



