176 THE SCOLYTTD BEETLES. 



COLOR. 



The color, except in a few genera, is of little taxononiic importance. 

 It ranges from pale yellow through yellowish red, reddish bro^A^l, 

 brown, and black. In a few genera the chitinous integument of the 

 elytra or other parts of the body is bicolored; in others the varie- 

 gated color is confined to the vestiture. Metallic and iridescent 

 colors are rare. 



VESTITURE. 



The vestiture is of considerable taxonomic importance. It con- 

 sists of scales, stout hairs, barbed hairs, plain hairs, fine pubescence, 

 gummy exudations, or adherents. The range in progressive modi- 

 fication of the vestiture appears to be from scales to stout hairs, from 

 barbed hairs to simple hairs, and from a sparsely pubescent to an 

 entirely glabrous body. 



SCULPTURE. 



In the sculpture of the body there is endless variety. It may be 

 rugose or smooth, the rugosity fine or coarse, tlie punctures sparse or 

 dense, arranged in rows or confused, regular or irregular in size, 

 irregularly distributed on given areas, etc. Some of the elements 

 of sculpture, such as the rugose or smooth pronotum, are of value 

 in separating the major and minor groups of the families, but the 

 characters of the rugosities and punctures are of special value in 

 defining the smaller groups and species. Concavities and convexi- 

 ties of the front of the head and of the apical declivity of the elytra are 

 often important generic, specific, and secondary sexual characters. 



ARMATURES. 



The armatures of the pronotum, head, and elytra are important 

 in the definition of genera, species, and sexes. The armature of the 

 head reaches its extreme development in the epistomal horn of 

 Cactopinus. The armature of the declivity is strongly developed 

 in Xylel)orus, Xylodeptes, and Eccoptopterus of the Cryphalinse; in 

 Pitijogenes and Ips of the Ipinse; in Hylocurus in the Micracinse; in 

 Monartlirum and Ampliicranus of the Corthylinse, and in most of 

 the genera of the Platypodinse. As a rule the modification from a 

 simple unarmed body to one with moderately or strongly armed 

 parts is correlated with other elements of progressive modification. 

 The serrate armature of the anterior margin of the pronotum is of 

 considerable taxonomic importance. The apical serrations are com- 

 mon in the Cryphalinse and Ipinse, but rare or absent in the other 

 subfamilies. The extremes in apical armature are found in Hypo- 

 ihenemus miles Lee, and in some other species, as, for example, the 



