CERAMBYCHXE 217 



veloped head, this being relatively unusually small in that genus, 

 in its very large, prominent and coarsely faceted eyes, more elongate 

 and even more acutely tuberculate sides of the prothorax, system of 

 sculpture and many other characters, of more or less weight from 

 the generic viewpoint. Its type is Pachyta spurca Lee., a large 

 pallid and coarsely sculptured species of the true Pacific coast fauna. 



Gaurotes Lee. 



If we limited this genus to those species having a protuberant 

 mesosternum, the only representatives in my cabinet would be 

 cyanipennis Say., and the Mexican multiguttatus Bates, which 

 diverge widely from each other in sculpture, coloration and vesti- 

 ture, showing how ineffectual it may sometimes be to base genera 

 upon a single character, however important it may seem. If, 

 however, we entirely abandon the mesosternum, the inconstancy 

 of which has long been known, and look broadly at the species 

 cyanipennis, cressoni and abdominalis , we find a constant pecu- 

 liarity of habitus, separating them widely from Acmcsops, and caused 

 by the short broad form of body, relatively small and transverse, 

 apically much narrowed and strongly, transversely biconstricted 

 prothorax and very small head, with the front not prolonged. This 

 composite habitus constitutes the real generic difference between 

 Gaurotes and Acmceops and, in this light, examining Acmceops 

 thoracica, bivittata and nigripennis, we find the identical facies of 

 Gaurotes, showing that they should form part of Gaurotes and not 

 of Acmcsops. The variety of sculpture and ornamentation within 

 the limits of Gaurotes, thus amplified, becomes very marked, but 

 to show that this fact has very little significance here, other than 

 to prove that the genus is composed of several subgeneric groups 

 three in number as far as now known, represented by bivittatus, 

 multiguttatus and cyanipennis, we have only to point out that 

 the greatest difference of this kind lies between the only two species 

 that are typical in regard to mesosternal structure; that is, cyani- 

 pennis and multiguttatus, one with shining' metallic, simply and 

 sparsely punctate and virtually glabrous elytra, the other with 

 duller black elytra, having dual vestiture, consisting of condensed 

 clusters of decumbent white hairs, with others erect, stiffer and 

 black intermingled. As proving the dominant importance of 



