PEELIMINAEY CLASSIFICATION OF SCOLYTOIDEA. 



173 



increase in the number of joints in the funicle. The exception to 

 tliis rule appears to be shown m the CorthyHnre where the one-jomted 

 and two-jointed funicles are characteristic of genera whicli, in certain 

 hues, have progressed further than genera in other subfamihes with 

 five, six, and seven joints. But it is by no means certam that these 

 Corthylmse are not highly specialized survivors of one of the most 

 ancient groups in which a one-jomted funicle became the fixed and 

 dominant character. 



It is interesting to note in Table II that the five-jointed funicle 

 is common to the greater number of genera. AU but two of the 

 classified genera with a five-jointed funicle fall in the subfamilies of 

 the IpidaB and the 

 large majority of 

 them m the first di- 

 vision ; while the 

 genera with a seven- 

 jointed funicle fall 

 in the last part of 

 Division II of the 

 Ipidse and in the 

 family Scolytidse. 



ANTENNAL CLUB . 



The antennal club 

 comes next to the 

 funicle as a bearer 

 of important generic 

 characters. The 

 range in modifica- 

 tions of form is 

 from a narrow, 

 somewhat c o m - 

 pressed and distinct^ annulated club like that of Hypothenemus and 

 Pityophthorus to the broad, thinly compressed, thickened at base, 

 obliquely truncated, solid conical, or separated jomt form. 



In 179 genera 123 have a more or less compressed and annulated 

 club, in 44 the club is thickened at base, and in 12 it is conical. In 

 170 genera 144 are annulated, 36 not annulated, and in 9 the jomts 

 are separated. In 136 genera 52 have sutura,! septa, 74 are without 

 sutural septa, and 10 have chitmized sutures. 



It r.ppears that the chitinized septum of the club, while variable 

 and paralleled in different genera, is a good generic character. The 

 septa vary m number from one to four and usually occur toward 

 the ventral margin, but may also occur toward the dorsal margin 

 of one or two sutures. The range of modification appears to be 

 59026°— 15 2 



Fig. 97. — Abnormalities ia the antennal funicle of Xylehorus tachy- 

 graphus: a, Anterior aspect of right antenna of female; b, posterior 

 aspect of club of a; c, anterior aspect of left antenna of male; d, pos- 

 terior aspect of club and funicle of c; e, anterior aspect of right ciub 

 and funicle of same specimen as c;f, posterior aspect of e; g, posterior 

 aspect of right antenna of another specimen; h, anterior aspect of 

 g. (Original.) 



