5gS 
THE STUDY OF INSECTS. 
is probable that the males of other species have similar 
habits, but how general this is has not yet been determined. 
The members of this family are among the most injuri¬ 
ous of the insect enemies of forest-trees. Frequently the 
trees are killed outright; in other cases, although the life of 
the tree is not endangered, the timber is greatly injured by 
the burrows. Occasionally fruit-trees are also injured by 
members of this family. 
Figure 729 represents one of the larger of our common 
, species, Dendroctonus tenebrans (Den-droc'to-nus ten'e- 
brans). This is a light-yellowish beetle, which 
lives under the thick bark of pine logs and stumps. 
It is about one fourth of an inch in length. 
The Clover-root Borer, Hylesinus trifolii (Hy- 
FlG * 729 * les'i-nus tri-fo'li-i).—This is a European insect, which 
has found its way to this country, and become a very serious 
pest in the Eastern States. It differs markedly from most 
of the members of this family in that it makes irregular 
burrows in the roots of herbaceous plants. It infests clover 
and allied plants. In many places in the East a large 
proportion of the two-year-old clover plants are infested by 
it. In the autumn larvae, pupae, and adults are found in the 
roots of such plants, and the adults remain here throughout 
the winter. 
The family AntiiribiDjE (An-thrib'i-dae) includes a small 
number of snout-beetles, in which the fold on the lower 
surface of the wing-covers is present, the pygidium of both 
sexes is undivided, the antennae are not elbowed, and the 
labrum is present. The larvae, as a rule, infest seeds and 
the stems of plants, some of them are said to have short but 
well-developed legs. The larvae of the genus Brachytarsus 
(Brach-y-tar'sus), which are very small, are supposed to be 
parasitic on scale-insects. 
