92 CONTRIBUTIONS TO CANADIAN PALjEONTOLOGT. 



6 and 7) and P. cristatus (fig. 8 and 9) are almost identical in form, dif- 

 fering only in size. Both are normally straight and excavated longitu- 

 dinally in the bark and surface of the wood, while those of P. punctaius 

 (figs. 3 to 5) are seldom straight and are excavated obliquely or trans- 

 versely through the bark and wood, and are often found with one wing of 

 the nuptial chamber extended to accommodate a second female, agreeing 

 almost exactly in this respect with that of the interglacial species. 



The genus Phloeosinus is represented by three or four described species 

 from Europe, one from the Himalayas, seven from Japan, one from 

 Mexico, one from Guatemala and four or five from America north of 

 Mexico. There are also several undescribed species that I have observed, 

 in collections, recorded from Texas, Colorado and Canada. I consider 

 this genus one of the oldest survivors of the Hylesinides group. It is not 

 improbable that it reached its maximum development during the Cre- 

 taceous period, and that its representatives were then common enemies of 

 the several species of Sequoia, Juniperus, Librocedrus, etc., having des- 

 cended probably with little change in habit or structure, and shared with 

 their surviving host plants the vicissitudes of the great and minor surface 

 disturbances and climatic changes from the Mesozoic to and through the 

 Cenozoic to the present. 



Therefore, the exclusive association of the surviving species of this 

 ancient genus of beetles with the survivors of a number of ancient genera 

 of Cupresseae and Taxodieae is of especial interest, since it seems to pre- 

 sent some evidence of a closer natural relationship between these groups 

 than has heretofore been recognized. Especially is this indicated in the 

 fact that one or more species infest the Sequoia, one of the oldest repre- 

 sentatives of the Taxodieae, and that so far none have been found to in- 

 fest Pinus, Picea or Abies, with which the Taxodieae are thought by 

 botanists to be more closely allied than to the Cupresseae. 



It seems quite important that an effort should be made to obtain more 

 material from the buried interglacial and other forests and fossil wood, 

 showing the work of insects, since it would lead to the determination of 

 some interesting and important facts regarding the habits of prehistoric 

 forms and their relation to primeval forest trees. 



