PRELIMINARY CLASSIFICATION OF SCOLYTOIDEA. 203- 



extends to one or both sides. These chambers are usually occupied 

 by the male of the polygamous colony or of the monogamous pair. 



Ventilating hurrow. — The ventilating burrow is the vertical burrow 

 which is located at more or less regular intervals in the roof of the 

 egg gallery and extends to or near the surface. It may serve the 

 purpose of ventilating the gallery, or, perhaps more frequently, as 

 a place for the storage of boring dust or an openmg through which 

 this dust may be ejected. Short burrows m the roof or sides may 

 be used as places in which the beetles turn around, or may serve the 

 purpose of nuptial chambers. 



Branching gallery. — The branching gallery may branch from the 

 central or nuptial chamber, or from the side of one of the main egg 

 galleries. In the latter case it is referred to as a lateral branch. 



Connecting galleries. — The connecting galleries are those of one or 

 more colonies which are connected either through the central cham- 

 ber or by lateral and primary galleries, as in many species of Pityogenes, 

 PityophtJiorus, Carphohorus , etc. 



Ternfiinal burrows. — The terminal burrows are excavated usually 

 by the female beetle at the farther end of a primary or a larteral gal- 

 lery, after the egg gallery is completed and while the brood is devel- 

 oping, as in Dendroctonus frontalis (Part I, figs. 51 and 52). 



Brood hurrows. — The brood burrows are those excavated by the 

 adults of a brood before the individuals emerge. They radiate from 

 the respective pupal cells of the individuals, as in Dendroctonus, cer- 

 tain species of Ips, etc. In the case of species with a single genera- 

 tion annually, the developed brood may overwinter in the brood 

 burrows. 



Hibernating burrows. — The hibernating or overwintering burrows 

 are those excavated in places other than that in which the broods 

 developed, such as those of Ips, in the twigs and branches, or in the 

 thick corky bark at the base of the trees, and those of PhlosopJithorus, 

 in the outer bark on the trunks of the living host trees. 



Food burrows. — The food burrow is excavated by the adult in the 

 same part of the tree in which it excavates its egg galleries, or in a 

 different part, as in Scolytus rugulosus and S. quadrispinosus, which 

 burrow in the living twigs at the base of a leaf stem or bud, and in 

 PJiloeosinus, which burrows at the base of living twigs. 



Trial burrows. — The trial burrows are those made by the parent 

 beetles in the bark of living trees preliminary to the general attack 

 and the excavation of successful egg galleries. 



Abandoned or failure gallery. — The abandoned or failure gaUery 

 is one which, through the resistance exerted by the vital part of the 

 plant attacked, the beetles are compelled to abandon or be drowned 

 in the resin or sap. 



