376 



amount required is from 12 oz. to 1 lb. to 100 cub. feet of space ; 

 between 75° and 85° F. an exposure of 36 hours is necessary, while 

 above 85°, owing to the rapid diffusion of the vapour, 24 hours is 

 sufficient. Since the substance is comparatively cheap and all un- 

 volatiUsed material can be kept indefinitely, the additional amount 

 required for a larger dose would be an insignificant item. Para- 

 dichlorobenzene is insoluble in water and does not deliquesce when 

 exposed to air, but completely volatilises ; it should therefore be kept 

 in an air-tight jar. The vapour is more than five times as heavy as 

 air;!fa sufficient quantity should be exposed in open receptacles 

 placed higher than the infested goods, e.g. bags of grain or stored pro- 

 ducts, which require fumigation. As certain insects, e.g. Calandra 

 oryzae, the rice weevil, C. granaria, the granary weevil, Triholium 

 confusum, the flour beetle, and mealworm larvae possess great tenacity 

 of hfe, proportionally larger doses should be used for them. Moths, 

 flies, ants, etc., are readily killed by using the strength given above. 

 The action of para-dichlorobenzene is primarily on the nervous system. 

 After exposure to the vapour for a few seconds, the insect displays 

 uneasiness, followed by spasmodic convulsions, and finally turns over 

 on its back. While in this position nervous and muscular reflex action 

 is noticed. In testing the action of the compound as a fumigant, 

 the writer concludes that it works excellently against pests of stored 

 products, case-bearing clothes moths, cockroaches, ants, museum pests, 

 etc., and is also an efiective substitute for potassium cyanide in collect- 

 ing beetles. The chemical and physical properties and composition 

 ofj^the compound are given. 



BuscK (A.). The European Pine-Shoot Moth ; a serious menace to Pine 

 Timber in America. — JJ.S. Dept, Agric, Washingion, D.C., Bull, 

 no. 170, 9th February 1915, 11 pp., 6 plates. 

 The European pine-shoot moth, Rhyacionia {Evetria) buoliana, has 

 been introduced into America on imported European pine seedhngs 

 and has become established in several localities in the eastern and 

 middle western states. [See this Revietv, Ser. A, ii, p. 701.] Some idea 

 of the extent and permanent character of the injury which this insect 

 can inflict may be gained from the illustration of a European pine 

 forest which has been infested for several years in succession, with 

 the result that the majority of the trunks are so twisted that their 

 value as timber is materially lessened. R. buoliana is confined to 

 pines, attacking all species, especially trees between 6 and 15 years 

 of age, but is often excessively destructive to younger and older trees, 

 though those over 30 years old are rarely affected seriously. Importa- 

 tions of pine from Europe into America take place in autumn, winter 

 and early spring. The young larvae lie dormant in the buds and are 

 easily overlooked. Many larvae die from overheating en route or 

 from unfavourable circumstances in handling or transplanting. This 

 is probably the reason why the species is as yet confined to few localities 

 and has only been found in nurseries and private parks supplied by 

 these infested nurseries. Infested twigs are noticeable in spring, but 

 the extent of the injury is realised later in the season, when new growth 

 is found to be destroyed or injured. The injured shoots become 

 deformed and though the injury straightens somewhat during succes- 

 sive years growth, it is always seriously detrimental to the timber. 



