59^ 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 tere- 

 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, Hylesinns trifolii (Hy- 

 Fjg. 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 ANTHRIBIDyE (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. 



