377 



If the pest is abundant, the trees have no commercial value whatever. 

 Several allied American species are known and like R. huoliana are 

 confined to the pine. They often do serious damage to pine forests 

 owing to the fact that there are two generations annually, but their 

 destructiveness cannot be compared \\'ith that of the European species. 

 The larva of the native species confines itself to a single bud or twig, 

 and the tree often recovers from the injury ^dthout permanent dis- 

 figurement. Injury is only serious when the native species are very 

 abundant. Moreover, each is confined to one or a few species of 

 Pimis, while the European form thrives on all species, and so has a 

 greater chance of spreading. R. huoliana in Europe is kept in check 

 to some extent by parasitic enemies, chiefly Ichneumonidae. 

 Parasitised larvae of native species have been observed in America, 

 and these parasites in time may attack R. buoliana, but will probably 

 not be very effective in controlling it. As the larvae are protected 

 within the buds from any insecticide, the only method of control is 

 pnming and destruction of infested buds. This is best done during 

 autumn and winter, the infested buds being easily recognisable by the 

 exudation of pitch at the base of the bud covering the entrance hole 

 of the larva. It is advisable to examine the trees again in spring, 

 since the injury is then much more apparent. In America, the work 

 of the larva in the autumn is more easily discovered than in Europe. 

 The fact that the species is stationary and only found within definite 

 parts of certain trees, renders control work comparatively easy. 



Beal (F. E. L.). Food of the Robins and Bluebirds of the United States. 

 U.S. Dept. Agric, Washi)igto)t, D.C., Bull.no. 171, oth February 

 1915, 31 pp., 2 figs. 



Investigations have shown that the food of robins and bluebirds 

 consists largely of insects and that the young feed upon them ex- 

 clusively. The following orders were found in the food of Planesticus 

 migratorius : — Hymenoptera, 3 ; Coleoptera, 196 ; Diptera, 1 ; 

 Lepidoptera, 9 ; Neuroptera, 1 ; Hemiptera, 12 ; Orthoptera, 3. 

 Sialia sialis, the eastern bluebird, was found to subsist upon insects 

 to the extent of five-sixths of its food, including Hymenoptera, 5 ; 

 Coleoptera, 127 ; Diptera, 2 ; Lepidoptera, 6 ; Hemiptera, 13 ; 

 Orthoptera, 8 ; Plecoptera, 2. In the food of S. mexicana, the follow- 

 ing have been found :— Hymenoptera, 1 ; Coleoptera, 24 ; Hemiptera, 

 2 ; in aS. currucoides, Coleoptera, 17 ; Hemiptera, 2. 



Sasscer (E. R.) & Hawkins (L. A.). A Method of fumigating Seed. 

 — U.S. Dept . Agric, Bur. Entoni., Washington, Bull. 186, 27th 

 February 1915, 6 pp., 2 figs., 1 table. 



A rehable method of destroying insects present m imported seeds, 

 without injury to the seed, is much needed. The ordinary methods, 

 such as exposure to heat, with or without moisture, carbon bisulphide, 

 and hydrocyanic acid in the presence of air, have been found unsatis- 

 factor^^ Experiments were conducted to determine whether more 

 gas could be forced into the crevices of the seeds if a partial vacuum 

 were first created than would be possible if the entrance of the gas 

 were dependent upon diffusion under normal atmospheric pressure. 



