PRELIMINARY CLASSIFICATIOX OF SCOLYTOIDEA. 195 



in other Rhynchophora. The bursa copulatrix, accordmg to Niisslin, 

 is present in Scolytus, Hylesinus, Polygraphus, Crijpturgus, and Hypo- 

 horus, much less evident in Carphohorus, Pityophthorus, Dryoccetes, 

 Taphrorychus, and Lymantor, and obscure or absent in Cryphalus, 

 Xyloterus, Xylocleptes, Thamnurgus, Ips, and Pityogenes. 



Conclusions as to whether or not the presence or absence of a given 

 element is primitive in the Scolytoidea, as based on morphological 

 interpretations, are becoming much less reliable than formerly because 

 of the frequency of parallel origin or disappearance of adaptive ele- 

 ments. 



NiissHn's (1911, pp. 333-338) classification as based on the female 

 organs of reproduction relates primarily to the presence or absence of 

 the cement gland and to its varying forms ; secondarily, to the presence 

 and character, or the absence, of the bursa copulatrix, and the char- 

 acter of the spermatheca and its seminal duct. 



When the characters of the female reproductive organs as given by 

 Niisslin are correlated with the external characters on which the 

 writer's prehminary classification is based, Scolytus falls into the sub- 

 family Scolytinse; Hypoborus and Thamnurgus into the Micracinse ; 

 Crypturgus and CarpJiohorus into the Crypturginse ; Polygraplius into 

 the Phloeotribinse ; Pityophthorus, Pityogenes, and Ips into the Ipinse ; 

 and Xyloterus into the Corthylinse; while Ernoporus, Cryphalus, 

 Taphrorychus, Lymantor, Dryoccetes, Xylehorus, and Xylocleptes fall 

 into the Cryphalinse. 



With a more comprehensive study of the female organs in num- 

 bers of species representing all the genera it will evidently be found 

 that there are some excellent taxonomic characters in the primary 

 elements and in their lines of progressive modification, which in com- 

 bination with other internal and external characters will be of special 

 value in defining groups of allied genera and in indicating relative 

 positions of the groups in the classification. 



Secondary Sexual Characters. 



There is a wide range in the types and position of the secondary or 

 external sexual characters, such as difference in the size of the body, 

 as in Hypothenemus, Stephanoderes , Coccotrypes, Xylehorus, and allied 

 genera, and the radical and contrasting differences in the structure, 

 vestiture, and sculpture of various external parts and areas. The 

 front of the head may be convex and glabrous in one sex and in the 

 opposite sex it may be flat to deeply concave, smooth, and shining, 

 punctured, and with dense and long pubescence or the margins fringed 

 with long hairs. The armature of the dechvity and the character of 

 the sutural impressions or broad excavation often vary to a remark- 

 able extent m the two sexes. The scape of the antenna may be stouter 

 to dilated and fringed with long hairs or not fringed. The funicle, 

 club, mouthparts, tibia, tarsus, abdominal tergites, and stemites, in 



