The bark beetles of Canada and Alaska

For example, the species of Pityophthorus and Myeloborus are found in the smaller branches and twigs; Conophthorus in the cones; 1ps in the larger branches, bole, and tops; Dendroctonu.r in the bole and sometimes in the roots; and Hylurgops and Hylastes in the lower portions and roots. [...] Mating t2 may take place in the gallery, on the surface of the host plant, or before the insects leave the host plant of the parents. [...] Pupation takes place in enlarged cells at the end of the larval mines in the inner bark, the cambium region, the outer bark, or, in the case of ambrosia beetles, in the cradles or the open mines. [...] The eyes are usually elongate-oval and are placed on the side of the head just posterioi to the antennal iniertions. [...] The disk is the central area of the pronotum and is the region most often used in classification.