2 PROCEEDINGS OF THE NATIONAL MUSEUM vol TO- 



as new. He also described a closely allied genus which he named 

 Hamletia in honor of Hamlet Clark, author of the Catalogue of 

 Halticidae. In 1875 appeared Chapuis'^ work on Chrysomelidae 

 with a detailed description of the genus Oedionychis which Horn in 

 his treatment of the North American species has translated nearly 

 literally. Chapuis pointed out an additional character, the open 

 coxal cavities, separating Oedianychis from other genera having 

 the globular claw. Von Harold ^° attempted to define clearly the 

 closely related genera Oedionychis^ Flomophoeta^ Aspicela, and 

 Asphaera. He distinguished them not only by the degree of infla- 

 tion of the claw joint, but also by the length of the first joint of the 

 posterior tarsus, which in Oedionychis is comparatively short. He 

 later published an account of the vittate species of this group.^^ 

 Meanwhile Jacoby ^^ was working on the Central American species^ 

 as well as publishing new species from South America, Africa, and 

 India. He followed von Harold's distinctions pretty closely, but in 

 one of his last papers " maintained that, although von Harold's 

 distinctions were in the main valid, there is in some instances a 

 gradation in the length of the first joint corresponding to the vari- 

 ability in the inflation of the claw joint. Horn's ^^ work on the 

 Halticidae of boreal America is the fullest and last account of the 

 North American species of the genus. He recognized 26 species 

 occurring north of Mexico, of which 5 were described as new. 



Since Horn's treatment of the Halticini little has been done with 

 the North American species of Oedionychis. The present paper is 

 an attempt to dispel some of the confusion in one group of the genus,, 

 namely, that consisting of Oedionychis quercata., ohsidiana, and 

 limbalis^ to incorporate species described since Horn's paper, and 

 to add new species and varieties. It seems certain that among such 

 closely related and variable forms as the Chrysomelidae more atten- 

 tion will be paid in the future to the numerous geographic or sub- 

 specific forms. I have described these at some length, although it 

 has not seemed desirable to dignify all of them with names. The 

 habitats and descriptions in this paper are based entirely on speci- 

 mens examined by the writer, unless otherwise stated. The synonymy 

 for the most part has been based on that of previous writers. 



The central habitat of the genus appears to be tropical America,, 

 and the species in America north of Mexico are comparatively few. 

 Only two species, Oedionychis viol<iscens and Oe. lugens^ are defi- 

 nitely known to occur on the Pacific coast. Oedionychis longula^ 



'■> Lacordaire's Genera de Col., vol. 11, 1875, p. 84. 



i<*Von Harold, Coleopterologische Hefte, vol. 15, 1876, p. 91. 



'1 Von Harold, Berliner Eutomologische Zeitschrift, vol. 25, 1881, p. 119. 



12 Jacoby, Biol. Cent. Amer., Coleopt., vol. 6, p. 1, 1880-1892. 



'3 Jacoby, Proc. Zool. Soc. London, 1905, p. 398. 



"Horn, Trans. Amer. Ent. Soc, vol. 16, 1889, p. 183. 



