186 



THE SCOLYTID BEETLES. 



Fig. IQi.— Pity oplithonissp.: Chitin- 

 ous elements of male reproductive 

 organs. See terminology, Divi- 

 sion 1, pp. 192-193. (Original.) 



from the same fundamental source as that from which the various 

 segmental lohes, sclerites, and appendages have developed. It 

 would appear best to refer to the chitinous element of the copulatory 



apparatus as repre- ^^,^,,^ 



senting certain seg- 

 mental elements 

 rather than to as- 

 sume that they have 

 been derived through 

 modification from 

 sclerites or append- 

 ages which had ex- 

 isted as such in a 

 primitive ancestor. 



It is quite evident 

 that element a rep- 

 resents the tenth sternite, h the tenth tergite, c 

 the ninth tergite, and d the ninth sternite, while hi 

 and 1)2 appear to represent elements of either 

 the tenth tergite or of both the tenth tergite and 

 tenth sternite. It might also be well to con- 

 sider in future investigations the possibility of 

 their representing the tenth pleurites or even 



an additional eleventh segment. The 

 wide range in the variation of these ele- 

 ments, the absence of some of them in 

 certain species, and the joining or fusion 

 of two or more in other species render 

 it exceedingly difficult properly to in- 

 terpret the primary and secondary ele- 

 ments, especially in the more complex 

 and in the apparently simple forms. 



The body, or element a, is present in 

 all cpecies. It is more or less distinct 

 from the other elements and is nearly 

 always suggestive of a modified sternite; 

 the femora {al ) appear to represent the 

 produced posterior angles, or apodemes, 

 of a typical abdominal sclerite, and the 

 lateral folds {a2) appear in some cases to 

 represent the hypopleurites, especially 

 in Tps, where they resemble end plates 

 and were so identified by Lindemann. The function of element a is that 

 of asheath or tube for the ejaculatorysack(^a) andfor the seminal valve 



Fig. 105.— Pityophtho- 

 rus bellus: End 

 plates and seminal 

 rod of male repro- 

 ductive organs, lat- 

 eral aspect. Note 

 contrast between 

 this and fig. 104. 

 See terminology, Di- 

 vision 1, pp. 192- 

 193. (Original.) 



Fig. 106. — Micracis suturalis: Posterior 

 elements of male reproductive organs, 

 dorsal aspect. See terminology. Di- 

 vision 1, pp. 192-193. (Origiaa'l.) 



