286 MEMOIRS ON THE COLEOPTERA 



is very deeply concave, more sparsely punctate and usually with 

 more marked pubescence; the anterior coxae, inner side of the 

 anterior femora basally and the hind margin of the prosternum are 

 densely pubescent, but elsewhere the hairs beneath are few in 

 number and very short, except the dense internal fringe of the hind 

 tibiae, and the upper surface is glabrous, opaque, green to black, 

 with more or less pale margins as a rule in our species, but becoming 

 polished throughout in certain tropical forms, such as viridicyanea. 

 Sexual modifications are extremely few and feeble and reside in the 

 dentition of the anterior tibiae, sometimes also in the longitudinal 

 abdominal impression of the male and relative lengths of the 

 hind tarsi. The Mexican species allied to mutabilis, as stated by 

 Bates, constitute an enormously difficult taxonomic problem; I 

 have therefore limited the tabular statement of species given below 

 simply to those forms at hand, occurring in the more subarctic 

 parts of the continent; they all have the hind coxae acute postero- 

 laterad and I have given most of them a specific status provi- 

 sionally; they are moderately numerous and as follows: 



Longitudinal cephalic ridge terminating anteriorly in a free apex. (CoxiNis 

 in sp.) 2 



Longitudinal cephalic ridge less elevated and without free anterior ex- 

 tremity, the corniform process of the clypeal apex lobiform or nearly 

 obsolete (LATEMNIS Thorns.) 10 



2 Lateral marginal bead of the pronotum becoming more or less notably 

 broad basally; front of the clypeus with a narrow longitudinal ridge 

 which extends partially up the posterior side of the apical process, 

 thereby giving that process additional strength in strut-like fashion; 

 pygidium uniform in coloration 3 



Lateral marginal bead fine throughout; front of the clypeus never not- 

 ably ridged, the apical process never conspicuously long; pygidium 

 always bicolored ! 5 



3 Body oblong-oval, not or but very feebly narrowed posteriorly, not- 

 ably depressed on the upper surface and dull, the head shining, some- 

 what metallic green, the pronotum deep obscure green, with a tawny 

 lateral stripe, which is variable in extent, the lateral margin, in- 

 cluding the bead, bright metallic green, the elytra invariably pale 

 red-brown, the sutural region, broadening slightly basally, very suf- 

 fusedly obscure greenish; pygidium uniform obscure testaceous, with 

 bright metallic-green lustre, having strong transverse interlacing 

 scratches and conspicuous stiff yellow hairs; under surface and legs 

 bright metallic green throughout; cephalic ridge with its free apex 

 dilated and very obtuse, the clypeal process broad, parallel or feebly 

 conical, not very high; prothorax relatively moderate, of the usual 

 form but only a little more than three-fourths as wide as the elytra, 



