ECONOMIC ZOOLOGY ENTOMOLOGY. 455 



a portion of the trunk which later clears itself of branches, hence only logs are 

 affected which, were it not for previous infestation by them, would yield only 

 the better grades of lumber. Douglas fir sawyers estimated a general loss in 

 the entire Douglas fir product of between 7.5 and 15 per cent due to pitch 

 seams. The depreciation is lowest in the Rocky Mountain region and heaviest 

 toward the coast, evidently corresponding to the respectively slower or quicker 

 growth of the trees in the respective localities and to the relative scarcity or 

 abundance of the moth in these regions. 



The author presents an account of its life history and habits and of the 

 nature of its injury. A period of three years is said to be required for the 

 development from egg to adult, 30 days being required for the incubation of 

 the egg and a similar period for the pupa. Two generations of larvae may be 

 found at any time of the year. 



In determining control measures readily accessible areas were selected for 

 detailed investigations. The results of the work are said to have made it evi- 

 dent that to accomplish any permanent good under general forest conditions it 

 is best to extend control over large areas. " Destruction of the larvae is the 

 only remedy that can be used to reduce an infestation. When the infested pitch 

 tube is located, it should be separated from the tree, the thus exposed larva 

 killed, and to insure cleaner healing the ragged edges of the wound should be 

 smoothed with a knife or small ax, after which they should be painted with 

 creosote or a similar preparation, to prevent reinfestation by insects or fungi. 

 The enlarging of the wound by the smoothing of its edges will also leave a 

 pitch blister in the tissues, but the ultimate result will not be nearly as dis- 

 astrous as from the untreated sesiid wound, since a clean healing from the 

 inside obviates much of the chance of its producing a circular seam. Freshly 

 vacated wounds might be treated the same way with profit." 



The Hessian fly situation in 1915, F. M. Webster and E. O. G. Kelly 

 {U. S. Dept. Agr., Office Sec. Circ. 51 {1915), pp. 10, figs. 5).— This circular pre- 

 sents diagrams which illustrate the seasonal development of the Hessian fly 

 from egg to adult twice during the year and a map showing approximate dates 

 in the fall, in various parts of the country, after which, under normal meteoro- 

 logical conditions, wheat may be sown without exjwsing it to serious attacks 

 by this pest. 



House flies, L. O. Howabd and R. H. Hutchison ( U. S. Dept. Agr., Farmers' 

 Bui. 679 {1915), pp. 22, figs. 15). — This bulletin, which supersedes Farmers' 

 Bulletin 459 (E. S. R., 25, p. 762), gives particular attention to preventive and 

 control measures. 



Further experiments in the destruction of fly larvae in horse manure, 

 F. C. Cook, R. H. Hutchison, and F, M. Scaxes {U. S. Dept. Agr. Bui. 2^5 

 {1915), pp. 22, pi. 1, fig. 1). — This is a report of work carried on in continua- 

 tion of that previously noted (E. S. R., 31, p. 653). 



This bulletin deals with investigations of the larvicidal efficiency of both 

 organic (anilin, beta-naphthol, cresylic acid, para-dichlorobenzene, formalde- 

 hyde, nitrobenzene, oxalic acid, and pyridin) and inorganic (arsenical dip, 

 chlorid of lime, Epsom salts, lime-sulphur, and sulphuric acid) substances, 

 together with bacteriological and chemical examinations of horse manure to 

 which many of these substances were applied. Of the inorganic substances 

 tested arsenical dip was the only one which when used in amounts considered 

 practical destroyed the larvae of the house fly. Of the organic substances 

 anilin, pyridin, and nitrobenzene, when used in certain dilutions, gave satis- 

 factory larvicidal results, but the cost precludes their use. 

 6318°— No. 5—15 5 



