194 



THE SCOLYTID BEETLES. 



Id. Spermatheca. 

 le. Spermathecal gland. 

 If. Seminal duct. 

 Ig. Cement glands. 

 111. Chitinous plates. 



Division 2. 



2a. 



Paired o\'iducts. 

 Ovaries. 



Classifications Based on the Reproductive Organs. 



In the classifications of Niisslin (1911), Fuchs (1911), and others, as 

 based on the male reproductive organs, we find, as we do in the classi- 

 fications based on the elements 

 of any single organ, that genera 

 and groups which are plainly 

 not closely allied are brought 

 together and those which by 

 the majority of external and in- 

 ternal characters are closely 

 alhed have been placed in widely 

 separated divisions or subdivi- 

 sions. When, however, the facts 

 of parallel modification are 

 taken into consideration and 

 the prmcipal elements are cor- 

 related with those of other or- 

 gans, the results are quite differ- 

 ent and the true taxonomic 

 value of the elements is recog- 

 nized. It is evident that a 

 study must be made of the male organs of reproduction in a much 

 larger number of species of all available genera before the true taxo- 

 nomic value of any of their elements can be determined and correlated. 

 NiissUn (1912) , who has given the subject of the female reproductive 

 organs (Fig. Ill) of Scolytidse late consideration, calls attention to the 

 taxonomic importance of the female genital organs in separating the 

 Adephaga and Polyphaga of the order Coleoptera and in distmguish- 

 ing the suborder Rhynchophora, which he claims is pecuUar in having 

 only two pairs of ovaria. 



The absence of a true ovipositor is apparently common to all scoly- 

 toid beetles, although in some species there are rudimentary parts 

 which in other Rhynchophora and Coleoptera belong to the ovipositor, 

 especially the genital palpi, which have been found only in Scolytus and 

 Hylesinus. The presence of paired or single cement glands appears 

 to be an important and more or less pecuHar element in the Scoly- 

 toidea, although it is said to be absent in Scolytus and Ernoporus, as 



Fig. 111.— Dendroctonus miens: Female reproductive 

 organs. See terminology, Division 1, pp. 193-194. 

 (Original.) 



