SCOLYTIDA. 87 
any illumination along the rows of punctures (except perhaps the sutural row) the elytra 
are termed lineato-punctate. 
All measurements, comparative or absolute, have been made with the microscope 
and a micrometer. Such measurements, if reliable, are most valuable aids to 
identification. 
Classification. 
A classification of the Scolytide based upon the structural characters of all existing 
genera has yet to be carried out; and much difficulty has been experienced by writers 
in grouping these insects, owing to the fact that in Scolytide, more than in any other 
Coleoptera, the parts of the body which afford the best differential generic characters— 
the mouth-parts, antenne, and legs—are often subject to great adaptive modifications 
among closely-allied genera and even species. This has led Lindemann to examine and 
employ for taxonomy such intimate structures as the armature of the proventriculus 
and of the male genitalia. These refinements, possible in the leisurely examination 
of abundant indigenous material, are out of place when dealing with a large exotic 
collection, and are unlikely to afford deep-seated characters. At present, after 
examination of representatives of almost every known genus, I do not see my way to 
classifying completely the Scolytide of the world; and in the grouping here adopted 
I have endeavoured merely to present some novel and, I believe, natural associations 
and to arrange the genera in a tolerably logical order. Nothing further is practicable 
till some stable and accurately definable characters are found to serve as a guide. 
Possibly such may occur in the exoskeleton, the examination of which, like that of 
the mouth-parts, is difficult and sometimes impossible without ample material. 
The characters hitherto employed being subject to adaptive modifications, none can 
be regarded as possessing a constant uniform value throughout the family. The 
number of joints in the funiculus is sometimes constant throughout a group, at other 
times so inconstant, owing to degeneration and the suppression of sutures in small 
species, that it will scarcely serve as the test of a genus. Levendal has shown that it 
may vary even in one and the same species. It is much easier to associate genera as 
possessing certain generally common features and habitus than it is to delimit the 
groups thus formed by the enunciation of any prominent constant character. 
There is, however, one character which serves to separate certain groups, the import- 
ance of which has not been recognized. In the Cossonide the tibize are unarmed on 
the upper margin, but are produced at the apex above the tarsal articulation into a 
mucro, which is usually recurved. In the majority of Scolytide the tibie, armed on 
the margin, are not so produced; but in the Scolyti and Camptoceri the anterior pair 
is constructed precisely as in the Cossonide, while the middle and posterior pairs 
may show the existence of secondary teeth, in addition to a less prominent mucro. 
