PRELIMINAEY CLASSIFICATIOlSr OF SCOLYTOIDEA. 169 



TAXONOMY. 

 MORPHOLOGICAL. CHARACTERS. 



The principal morphological characters adopted by the writer to 

 distmguish the famiHes, subfamilies, and genera, and the major and 

 minor divisions of each are to be found in the external anatomy of 

 the imago. However, some consideration has been given to the 

 location of correlated characters in the internal anatomy and in the 

 physiological characteristics of the different stages of development 

 from the egg to the imago. 



It has seemed to the writer that in order to have a classification 

 which would indicate natural positions and lines of modification, 

 and at the same time be simple and practicable, we should endeavor 

 to locate and utihze, as far as possible, external characters which 

 are readily available for examination by a hand lens or the micro- 

 scope without serious mutilation of the specimens by those who make 

 use of the systematic tables and descriptions. The small size of most 

 of the scolytoid beetles renders it difficult and tedious to examine 

 the minute and obscure elements of the external and internal anat- 

 omy, such as the mouthparts and the digestive and sexual organs. 

 It is very important, in fact essential, that the taxonomist should 

 study in detail, and comprehensively, the various elements of exter- 

 nal and internal anatomy in order to have a broad basis for his con- 

 clusions, but the general student and investigator should not be 

 required to go to such extremes in order properly to mterpret the 

 conclusions. Therefore it has been the object of the writer to con- 

 form to the simple method of expression rather than to that involving 

 a complexity of detail. 



The principal character-bearing parts of the external anatomy 

 which appear to serve as the best taxonomic guides toward a natural 

 system of classification are mentioned in the following pages merely 

 as a basis for the prehmmary classification, which is subject to 

 revision in the more detailed treatment of the several subfamilies. 



SUPERFAMILY CHARACTERS. 



The superfamily is at once separated into two primary divisions 

 by the relative length of the first tarsal joint, and the subdivisions, 

 sections, and famihes are distinguished by characters of the tibia 

 (PL IX). It is interestiag to note that while the most dominant 

 character is found in the first joint of the tarsus, the modification 

 of this joint withia the famihes, subfamilies, and genera is of minor 

 importance. The same, to a lesser degree, may be said of the tibia, 

 in which the character of the apical angles is constant ^\dthin each 

 subdivision of the superfamily but the modification of these angles 



