PEELIMINAEY CLASSIFICATION OF SCOLYTOIDEA. 



181 



the eighth to be uncovered in both sexes in three genera, uncovered 

 in the male and covered in the female in 13 genera, and covered in 

 both sexes in 3 genera. 



Accoixling to the writer's classification, the 31 genera in which 

 species were examined by Niisslin and the writer represent the 

 following subfamilies : 



Table III. — Abdominal tergites in the subfamilies of Scolytoidea in which species were 

 examined by Niisslin and the writer. 



Subfamily. 



Cryphalinge 



Ipiiiffi 



eorthylinse 



Micracinae 



Crypturginae... 

 Phloeotribinae . 



Hylesininse 



Scolytinse. .... 

 Platypodinae . . 



Eighth ter- 

 gite uncov- 

 ered in both 

 sexes. 



Genera. 



Eighth ter- 

 gite uncov- 

 ered in male, 

 not in female. 



Genera. 



Total. 



Eighth ter- 

 gite covered 

 in both sexes. 



Genera. 



From the foregoing it will be seen that the characters of the seventh 

 and eighth tergites are paralleled in widely separated genera and sub- 

 families. The writer has found that the eighth tergite may or may 

 not be exposed or covered in the same genus or in individuals of the 

 same species, especially in Platypus, where the eighth tergite is of the 

 same or similar form in both sexes and may be covered or not, de- 

 pending upon the expansion or contraction of the abdomen. It is 

 evident that a much more extensive study of these elements is neces- 

 sary before any conclusions are warranted as to their taxonomic 

 value or lines of progressive modification. In a number of genera 

 the seventh or eighth tergite, or both, is exposed beyond the apex 

 of the elytra and is either obhque, declivous, or vertical. The ninth 

 and tenth tergites are absent as such or are modified into elements 

 of the genital organs. 



ABDOMINAL SPIRACLES. 



According to Niisslin (1911) and Fuchs (1912) the number of func- 

 tional abdonfinal spiracles (stigmata) ranges from five to seven. The 

 larvae and pupae, so far as studied by the writer, have eight. 



The spiracles are variable in structure and doubtless, upon further 

 investigation, will furnish excellent taxonomic characters. The 

 writer, however, is doubtful as to the phylogenetic significance of the 

 variability in number. The genera given by Ntissfin (1911, pp. 2-5) 

 and Fuchs (1912, pp. 13-14) which are represented by species having 



