VI THE SCOLYTID BEETLES. 



Preliminary Gi^assification op the Superpamily Scolttoidea — Contd. 

 Taxonomy — Continued. 



Physiological characteristics — Continued. Page. 



Classification of the galleries 204 



Egg galleries 204 



Larval mines 204 



Types and subtypes of egg galleries 205 



Relation of types of galleries to the subfamilies and fam- 

 ilies 206 



Taxonomic relation between the beetles and their host plants 207 



Part of plant selected by the beetles 207 



Condition of the plant 208 



Relation of the species of beetles to the systematic position of 



their host 208 



Range of host plants 208 



Associations of species of beetles and species of plants 209 



Summary of taxonomic e^ddence fxu-nished by host relations. 209 



Geographical distribution in its bearing on taxonomy 210 



Review of taxonomic characters and characteristics 211 



Morphological characters 212 



Physiological characteristics 213 



Correlation of morphological and physiological elements 213 



Parallel modifications 214 



Reversals 214 



Progressive modifications 215 



Examples of progressive modification 215 



Statistical taxonomy 216 



The species 216 



Varieties, races, etc 216 



The genus 217 



Nomenclature 218 



Types of genera 219 



Genus Scolytus Geoffrey 219 



Genus Ips De Geer 220 



Genus Tomicus Latreille 220 



Genus Hylastes Erichson 221 



Genus Cryphalus Erichson 221 



Genus Hypothenemus Westwood 221 



Genus Polygraphus Erichson 222 



Genus Lepisomus Kirby 222 



Description of a new genus and species 222 



Preliminary classification of the Superfamily Scolytoidea 224 



Key to the families 224 



Division 1 224 



Subdivision A 224 



Family Ipidse , 224 



Subdivision B 225 



Family Scolytidae 225 



Family Scolytoplatypodidse 225 



Division II 225 



Subdivision C 225 



Family Platypodidse 225 



