513 



Dendrodonus micans, Kug., was found in old spnico trees ; 

 Xylechinus pilosus, Ratz., in dead and dying spruces and also in silver 

 firs and larches ; PolygrapJms poh/graphus, L., in spruces ; P. siibo- 

 pacus, Thorns., in spruces, less frequently in pines ; Crypturgus 

 pusillus, Gyll., and C. cinereus, Hbst., underneath the bark of spruces 

 and pines ; Hylurgops glabratus, Zett., and H. palliatus, Gyll., in 

 spruces and pines ; Hylastes ater, Payk., in pines ; H. cuniculanns, Er., 

 in spruces ; H. opacus, Er., in pines ; Ips sexdentatus, Born., under- 

 neath the bark of old pines, less frequently in spruces ; Ips 

 typographus, L., in spruces, there being probably two generations. 



Ips duplicatus. Sahib., which is very rare in Western Europe, is 

 widespread in Russia, in the spruce woods ; its life-history differs 

 somewhat from that of the previous species. Young beetles, having 

 emerged after hibernation, were observed to attack spruce, under the 

 bark of which they gnawed mines. They did not oviposit in these 

 and were evidently only feeding ; in the first half of June they began 

 to mine in spruces other than those previously attacked, and by the 

 middle of July young beetles were already present underneath the 

 bark. Ips acuminotus, Gyll., after the two species of Myehphilus, is 

 the most common Scolytid found in pines ; the beetles are on the 

 wing in the first half of June. The young beetles appear underneath 

 the bark in the second half of summer, gnawing at the larval mines. 

 In August these beetles pass to ether trees, in which they mine and 

 hibernate. 



Neotomiciis proximus, Eichh., N. laricis, F., and N. suturalis, Gyll., 

 were found in large numbers in fallen pines ; in rare cases the first and 

 last were also present in spruces. Pityogenes chalcographus, L., is very 

 common in both spruces and pines. P. quadridens, Hart., and P. biden- 

 tatus, Hbst., occur in pines, and Pityophthorus micrographus, Eichh., in 

 spruces. One example of P. lichtensteini, Ratz., was found in a pine 

 branch in which it oviposited. Dryocoetes autographus, Ratz., occurs 

 in spruces and D. alni, Georg., although previously rare, has recently 

 become very common in alders {Alnus incana, L.) ; the beetles 

 avoid boring in very young and juicy bark. This species is 

 gregarious, many beetles using the entrance-mines bored by other 

 individuals ; beneath the bark a common rosette is formed, from which 

 the brood-galleries, sometimes over twenty in number, radiate in all 

 directions. The brood-galleries are made by both sexes at different 

 stages of maturity ; each mature female continues the boring, laying 

 eggs in the cells, while the young beetles gnaw the walls of the mine 

 and frequently penetrate into mines other than their own. At the end 

 of the summer all the mines become much entangled. Oviposition 

 begins only a month after the beetles have emerged, this time being 

 occupied in feeding. Cryphalus saltuarius, Weise, attacks young 

 diseased or weak spruce trees, and C. abietis, Ratz., and Ernoporus 

 tiliae, Panz., lime trees. Trypophloeus alni, Lind., was first found in 

 alders in 1914. Xyloterus sigmitus, F., is very common in alders and 

 pines. X. lineaius, Oliv., is frequently found in spruce and pine ; in 

 April it attacks spruces damaged by wind in company with Hylastes 

 palliatus. Xyleborus {Anisandrus) dispar, F., attacks alders and 

 X. cryptographus, Ratz., poplar trees. 



(C416) o 



