TIMHEK-liEETLES AND PINE .SAWYEHS. 



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

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



Tomicim piiii Say, the northern pine bark-beetle, is destructive to pine forests in the Xorth 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. callifiraplius (ierm., a 

 similar species to tlu^ two preceding and about e(pially destruc 

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

 and T. cwlatus Zinim. and T. avulsns Eich. also infest White Pine. 



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

 mentioned Crypt urgus imsUlns Oyll., llnJiirnops glahrutvn Zett., 

 and several species of Hylastes and Dryocretes. 



The remedies to be employed against these insects are i>rac- 

 tically the same as for tli(^ destructive pine bark-beetle. 



TIMBER-BEETLES AND OTHER SCOLYTID^. 



While the majority of the pine-infesting Scolytida^ 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 aiul 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 „ „ ^ ,, . . „. ■ 



^ ^ Fig. 7. — Galleries of lomicun cacngraphus 



sawdust which they eject from the " pin-hole" entrance to their on wooii un.ier bark of piue (uriginaii. 



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



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

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

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

 tratt d at fig. 9. 



The same remedies advised against bark-beetles will x^rove 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, /'. sparsus Lee, cariniceps Lee, pullns 

 Lee, lauttis Eich., plan iatiis 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 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 SAW^YERS AND OTHER BORERS. 

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

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



Fig. 8. — Gnathotrichus ma. 

 teriarius; beetle, enlarged ; 

 antenna, atill more en 

 larged at left (Marx del.). 



