PEELIMINAEY CLASSIFICATIOjST OF SCOLYTOIDEA. 219 



ancient groups and common, closely allied, and variable forms, that 

 the difference between two species in one genus may be equivalent 

 to or gi'eater than that between two alhed genera. In a like manner 

 the difference between two genera may be almost equivalent in rank 

 to that between two alhed subfamihes. Therefore the fact that a given 

 group of individuals or agroup of species appears to represent aposition 

 of lower rank than that of an alhed species or genus is not sufficient rea- 

 son that it should be designated as a subspecies or subgenus. In other 

 words, it is the ^vriter's opinion that if a group of individuals is suffi- 

 ciently distinct from allied groups to justify its designation by a name, 

 it should be recognized as a species ; and if, on tlie other hand^ the group 

 is connected with allied forms by such a number of intermediate forms 

 as to render its specific distinction doubtful, it should be included with 

 other variable types under a species name, and that the same principle 

 should hold in regard to the genus. 



All of the purposes served by the subspecific designation can be 

 served just as well, if not better, by classifying the individuals of a 

 species into major and minor divisions, sections, etc., and letting these 

 represent the same conception as that represented by the named sub- 

 species, and on the same principle the divisions and subdivisions of a 

 genus will serve the same purpose as if designated by names. 



TYPES OF GENERA. 



Difference of opinion among systematists who have worked on the 

 scolytoid beetles, guided as they have been by different rules and con- 

 ceptions as to what constitutes a vahd genus, has led to much uncer- 

 tainty and confusion as to some of the older names for the genera of 

 our common species. Therefore it seems necessary that the author 

 should present the evidence which appears to him to be conclusive in 

 regard to the generic names and the synonymy of Scolytus, Ips, Tomi- 

 cus, Cryphalus, Hypothenemns , etc. 



Genus SCOLYTUS Geoflfroy. 



It has seemed to the writer that there is not sufficient reason or 

 authority for the suppression of the name Scolytus as proposed and 

 clearly defined by Geoffroy (1762, p. 309). The single "species" of 

 the "genus" recognized by him was at the same time (p. 310) indi- 

 cated by a number, the genus name (Scolytus), and a reference to a 

 figure (Vol. I, pi. 5, fig. 5), and the characters were more clearly 

 defined in a description. 



Miiller (1764, p. xiv) recognized the genus Scolytus Geoff, and re- 

 ferred to the original description and figures. 



Schaeffer (1766, Tab. CXII, figs. 1, 2, 3, 4) red escribed the genus 

 Scolytus and described and figured the species indicated by Geoffroy, 

 but did not name it. 



