600 



given of Myelophilns {Blasfophagns) pinipcrda and M. minor, the 

 adults of which cause primary injury, that of the larvae being mostly 

 secondary. Large stacks of firewood and forest fires favour the increase 

 of these species. The most common of the other pine bark-beetles 

 are Pityogenes qiiadridens and Hylas/cs ( Hylurgops) palliatns ; Ips 

 proximus, I. acuminatus and /. suturalis are fairly common, the 

 last-named being the most injurious in the opinion of the autlior, 

 who considers forest fires to be the chief cause of its spread. /. laricis 

 is common, but unimportant as regards forestry. /. sexdeniatus and 

 Pityogenes bidentatus are somewhat scarce and, like Crypturgus pnsilhts 

 and C. cineretis, do no harm. Pithy ophthonis lichtensteini is an 

 entirely primary, rare pest of pines. Hyiastes brunneus is a very rare 

 species. 



A number of Finnish bark-beetles breed under the bark of spruce 

 stems and branches. Dendroctonus micans, which is rare, occupies 

 a special position among them, as it infests living trees only, though 

 in many cases observed the latter were suffering from fungus attack. 

 Ips iypographus, Pityogenes chalcographus, Polygraphus subopacits 

 and Hyiastes palliatus are very common, the last-named being of 

 little importance, while Ips typographus is the most harmful. Poly- 

 graphus poligraphits, Hyiastes (Hylurgops) glabratus, Crypturgus 

 hispididns and C. cinercus are common ; the first of these is a primary 

 pest, capable of doing much harm. Among fairly common species 

 are Xylechinus pilosns, Cryphalus saltuarius and Ips suturalis ; they 

 can do primary injury. Damage by storms is said to be the chief 

 cause of the increase of the spruce bark-beetles. Infestations reach 

 their maximum two or three years after storms and then decrease 

 year by year. 



Tn birch woods Scolytns ratzeburgi does important local damage 

 to trees injured by fires or storms. 



Xyloterus lineatiis, common on pine and spruce, and also found on 

 larch, is the only bark-beetle breeding in the wood itself ; A^. signatiis 

 and X. domesticus breed in the wood of deciduous trees. All three 

 are usually found in areas damaged by storms. 



A knowledge of the date of the larval period is essential for successful 

 control. The larvae of Myelophilus piniperda and M. minor chiefly 

 occur in June, and those of Ips typographus, Pityogenes chalcographus 

 and Xylotertis lineatiis in July. Polygraphus spp. and Scolytus 

 ratzeburgi hibernate in the larval stage, and may be found in that 

 stage throughout the year. 



Kr.vus (R.). Sobre el Estado actual de la Destruccion de la Langosta 

 con el Cocobacilo acridiorum d'Herelle. [The Present Situation 

 with regard to Locust Destruction by Coccobacillus acridiorum, 

 d'Herelle. 1 — Rev. Inst. Bad., Buenos Aires, iii, no. 1, Januarv 

 1921, pp. ^297-300. 



The author discusses the views of various investigators regarding 

 the value of Coccobacillus acridiorum, d'Her., in the work of locust 

 destruction, and quotes these as confirming his own opinion [R. A.E., 

 A, V, 133] that this organism, when increased to its greatest virulence, 

 can kill the locust only by peritoneal injection and not by ingestion, 

 and, moreover, that it is a normal inhabitant of the intestine of the 

 locust. 



