TIMBER-KEETLES AND PIXE SAWYERS. 



57 



species by the structure of its aiiteuiiiu and by the toothed apex of the elytra or wiug-covers. Its 

 mine is shown as it appears ou the undei' side of the barlv of a tree at iig. 7. 



Tomiciis 2>i>i> Say, tlie 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 iu structure as in habit, 

 but is less injurious larthcr South. T. caUif/raphus Germ., a 

 similar species to the two preceding and about eipiiilly destruc 

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

 and 2'. calatus Zinim. and T.andsus Eich. also infest White Piue. 



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

 mentioned Cryptur(iuf; j*m.s'(7/»s GylL, Ilnhiyi/ops (jlahralus Zett., 

 and several species of Ilylastes and Dryocii-tes. 



The remedies to be employed against these insects are prac- 

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



TIMBER-BEETLES AND OTHER SCOLYTID^. 



While the majority of the pine-infesting Scolytida' breed 

 between tlie 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 Pityoplithorus conipei-ila Sz., inhabits the 

 cones. 



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

 is from their attacks on living trees. They do comiiaratively 

 little damage to timber, except as they looseu 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. The presence of 

 these beetles in a tree is manifested by the little piles of white 

 sawdust which they eject from the " j)in-hole'' entrance to their 

 galleries. 



Fig. 7. — Galleries of Tomicus caci»jraphug 

 on wootl uodc-r bark of piiie (original). 



The pine tjmber-beetles are found in the genera Gnathotrichus. Xyloterus, Xylebo- 



rus, and Platypus. GnaihoiridniH materiurins Fitch is the commonest of three species of the 

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

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

 trated at flg. 9. 



The same remedies advised against bark-beetles will prove valuable 

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

 accomplish the destrui'tion 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. sparsits Lee, cdrinici'jjs Lee. jyuUits 

 Lee, hiutiis TSi\ch.,ph(fiiatiis Lee, are all well-known pine species. The genus 

 Hypothenemus 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 i)rivate 



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 SA'WYERS AND OTHER BORERS. 



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

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



Fig. 8 — linathotrichus ma. 

 teriarhts; beetle, enlarged: 

 antenna, still more eu- 

 larsed ,Tt left (ilars del.). 



