192 



THE CANADIAN ENTOMOLOGIST, 



They vary from one to a little over eight millimeters in length. 

 Crypturgus ptiiilhis is one of the smallest species, and Dendroctonus 

 valetis probably the largest. The legs are rather small and weak, as 

 becomes their habits. The antenna are short and geniculate, with an 

 extremely large club, which is usually annulated. The vast majority of 

 Scolytids cut their breeding-tuiuiels in the bark or wood of trees or shrubs. 

 The chief North American exceptions are leferred to below. 



The burrows of the Scolytida? are of great interest, and often of 

 remarkable regularity and beauty. The burrows of many species are so 

 characteristic that it is often easy to guess which species has been at work 

 from an examination of the tunnels and galleries alone. (Figs. lo and 1 1.) 



IT^^ 



Fig. io. — Burrows ot .SloIn ticUe. 



Fig. II. — Burrows of .Scoli tiil.u. 



About one-quarter of our North American species infest coniferous 

 trees, the Pines and Spruces being especially subject to attack. Of 



