16 GEO. H. HORN, M. D. 



While in all parts of the coleopterous series an abundant series is 

 useful, in Heterocerus a very large series is absolutely necessary, and 

 the more specimens examined the greater the difficulty in defining 

 the species and the greater necessity for the use of judgment in 

 placing specimens. About half of the species are separable by 

 structural characters of a positive nature, while others, especially 

 coUaris and undatiis are extremely difficult to define. 



HETEROCERUS Bosc. 



H. gnatho Lee, New Species, 1863, p. 74. 



labratus Lee, List Col. N. A. p. 35 ; labiatiis ( || ) Lee, New Species, 1863, p. 

 75, err. typ. 

 H. pallidas Say, Journ. Acad, iii, p. 199; edit. Lee. ii, p. 127. 

 H. ventralis Mels., Proc. Acad. ii. p. 98. 



labiafus Kies., Revis. Linn. Ent. v, 1851, p. 282. 

 H. undatus Mels., Proc. Acad, ii, p. 98; Kies., loc. cit. p. 293. 



var. cnniculus Kies., loc. cit. p. 283. 



var. substriatus Kies., loc. cit p. 290. 

 miser Kies., loc. cit. p. 290. 



var. mollinns Kies., loc. cit. p. 289. 

 fatuus Kies., loc. cit. p. 292. 

 H. g-emmatus u. sp. (idem LeConte in cab.) 

 H. brunneus Mels. Proc. Acad, ii, p. 91. 



flavipes Lee, mss. 

 H. Schwarzi n. sp. 

 H. coUaris Kies., loc. cit. p. 292. 



ornatidus and fuscipes Lee, mss. 



vilis Sharp, Biol. Cent. Am. i, 2, p. 773. 

 H. tristis Mann., Bull. Mose 1853, iii, p. 218. 

 H. pusillus Say, Journ. Acad, iii, p. 200; edit. Lee ii, p. 128. 



Umbatus Kies. Germ. Zeit. iv, 1843, p. 215, pi. 3, fig. 13. 



luteolus Lee, New Species, p. 75. 



americaniis Sharp, Biol. Cent. Am. i, 2, p. 772. 

 H. auroraicans Kies., loc. cit. p. 287. 



Among the species described by Dr. Sharp, from Mexico, vehttinus should be 

 compared with gnatho Lee, and mexicamis with coUaris. 



EXPLANATION OF PLATE I. 



Fig. 1. — H. gnatho % Lee. 

 " 2.— H. pallidas % Say. 

 " 3. — H. ventralis % Mels. 

 " 4. — H. ventralis J var. 

 " 5. — H. gemmatus % Horn. 



" 6.— H. undatus 9 Mels. 



" 7. — H. collaris % Kies. The usual longer form from Arizona. 

 " 8. — H. collaris small variety. 

 " 9. — H. tristis 9 Mann. 



" 10.— H. Schwarzi ? Horn. 



" 11. — H. auromicans Kies. 



" 12. — H. pusillus Say, var. Umbatus Kies. 



" 13. — Head of gnatho % . 



" 14. — " brunneus % . 



" 15. — " gemmatus 'J, . 



" 16. — " pusillus % . 



" 17. — Mandible of pusillus % . 



