TIMBER-BEETLES AND PINE SAWYERS. 



57 



species by the structure of its antennae and by tbe toothed apex of the elytra or wing-covers. Its 

 mine is shown as it appears on the uuder side of the bark of a tree at fig. 7. 



Tomicus pini Say, the northern pine bark-beetle, is destructive to pine forests in the North in 

 a very similar manner to the preceding species, which it much resembles in structure as in habit, 

 but is less injurious farther South. T. calligraphus Germ., a 

 similar species to the two preceding and about equally destruc 

 tive, abounds in the pine woods of both the North and South, 

 and T. ccelatus Ziuim. and T. avulsus Eich. also infest White Pine. 



Among other well-known white-pine bark-beetles may be 

 mentioned Crypturgus pusillus Gyll., Hylurgops glabratus Zett., 

 and several species of Hylastes and Dryoccetes. 



The remedies to be employed against these insects are prac- 

 tically the same as for the destructive pine bark-beetle. 



TIMBER-BEETLES AND OTHER SCOLYTID2E. 



While the majority of the pine-infesting Scolytidae breed 



between the bark and the wood, a considerable number, called 



timber-beetles, live entirely within the sapwood ; others, 



the twig-beetles in the small twigs and branches, and a third 



group, represented by Pityophthorus coniperda Sz., inhabits the 



cones. 



The chief danger from the bark-beetles, as has been shown, 



is from their attacks on living trees. They do comparatively 



little damage to timber, except as they loosen the bark and thus 



afford ready access to water and mold and to other destructive 



insects. The timber-beetles, or . ambrosia beetles, as they are 



sometimes called, live almost exclusively in greenwood, pre- 

 ferring that which is slightly injured, of impaired vitality, or 



such as has been newly felled, but they often attack and kill 



healthy growth, and in the process of their work in timber cause 



a staining or "bluing" which- entails a still greater loss than 



results from their direct attack to living trees^j/The presence of 



these beetles in a tree is manifested by the little piles of white Flo 7 ._ GaUeries ot Tomicus eacographul 



sawdust which they eject from the " pin-hole" entrance to their on wood under bark of pine (original). 



galleries^/The pine timber-beetles are found in the genera Gnathotrichus, Xyloterus, Xylebo- 



rus, and Platypus. Gnathotrichus materiarius Fitch is the commonest of three species of the 

 genus, all of which attack pine. This species is shown greatly enlarged 

 at fig. 8, and its characteristic galleries in the wood of pine are well illus- 

 trat d at fig. 9. 



The same remedies advised against bark-beetles will prove valuable 

 against the timber beetles. Kerosene emulsion or a carbolated wash would 

 accomplish the destruction of the timber-beetles even after they have 

 attained entrance to a tree, provided the application be made in time. 



The twig beetles are represented by the genera Pityophthorus and 

 Hypothenemus. Of the former genus, P. sparsus Lee., cariniceps Lee., pullus 

 Lee., lautus JZich.,plagiatu8 Lee., are all well-known pine species. The genus 

 Hypothenemns inhabits alike deciduous and coniferous trees. 



Remedies are the same as for bark-beetles. Pruning and burning 

 infested twigs and branches and the clearing away and burning of brush 

 _ heaps during winter are indicated. For choice ornamental trees in private 



grounds and in parks plugging the "pin holes" with wire and stimulating the trees with manures 



and fertilizers to assist them to recuperate from attack are advisable. 



PINE SAWYERS AND OTHER BORERS. 



Of all the insects that occur in pine timber the Cerambycid, or long-horned beetles, of the 

 genus Monohamrnus, are the best known, and are credited with being the most destructive. If 



FIG. 8. (rnathotricltug ma. 

 Uriariut: beetle, enlarged ; 

 antenna, still more en- 

 larged at left (Marx del.). 



