ECONOMIC ZOOLOGY ENTOMOLOGY. 55 



October, 1907, a larse part of the cultivated lands in the lower part of the 

 Humboldt ^'alley had been overrun by vast numbers of mice. The yield of hay 

 had been reduced by one-third ; potatoes and root crops were largely destroyed ; 

 many alfalfa tields were ruined by the mice eating the roots of the plants; antl 

 the complete destruction of this, the chief crop in the valley, was threatened. 

 The height of the abundance was reached in November, when it was estimated 

 that on many ranches there were from 8,000 to 12,000 mice to each acre." 



The preparations in general used by the ranchmen in combating the pest con- 

 sisted of wheat treated with a strong solution of yellow phosphorus in carbon 

 bisulphid. As the result of its extensive employment in the valley, California 

 quail, an introduced species, were decimated, and magpies, crows. meado\^' 

 larks, and smaller seed-eating birds suffered extremely. Several attempts by 

 ranchmen to introduce contagious diseases among the mice by means of adver- 

 tised bacterial preparations failed. " The scourge of mice swept over about 

 four-fifths of the cultivated area in the lower part of Humboldt Valley. Of 

 about 20,000 acres in alfalfa, about 15,000 were so seriously injured as to re- 

 quire plowing and replanting. Over most of this area the alfalfa was replaced 

 by grain crops for the season of 1908, at great expense and loss, since good 

 alfalfa lands pay gross returns of from $60 to $70 per acre, while good grain 

 crops return only $35 or $40 per acre." This is said to be the first recorded in- 

 stance of an eruption of field mice in North America attaining the proportions 

 of a plague. 



Experiments conducted by the Biological Survey demonstrate that the mice 

 can be effectively destroyed in winter by alfalfa hay poisoned with strichnia 

 sulphate, and such poisoning is considered the most practicable. Ordinarily 

 poisoning in winter will prevent the necessity for it in summer. When, how- 

 ever, mice appear in alarming numbers in the spring they should be promptly 

 suppressed, since under these conditions a plague may be well established by 

 fall. Otlier remedies are considered at some length. Attention is also called 

 to the part played by natural enemies of the mice and the importance of their 

 protection. 



Proceedings of the twenty-first annual meeting of the American Associa- 

 tion of Economic Entomologists (Jour. Econ. Ent., 2 {1909), ISio. 1, pp. 1-66, 

 pi. 1 ) . — This is the report of the meeting held at Baltimore, Md., December 28 

 and 29, 1908, a preliminary note on which has been given (E. S. R., 20, p. 496). 

 In addition to addresses, papers, and discussions, the report includes the busi- 

 ness proceedings, including reports of the secretary, committees on legislation, 

 nomenclature, insecticides, membership, memorial resolutions, etc., the constitu- 

 tion as aodpted, and a list (pp. 14-16) of 89 common names of insects adopted 

 at tlie meeting. 



President S. A. Forbes, in his annual address, discusses the Aspects of Prog- 

 ress in Economic Entomology (pp. 25-35). Attention is called to the rapid 

 development of economic entomology in the last 15 years, the value of statistical 

 methods in determining the range of variations, the developing methods of 

 ecology, the breeding of insect-resistant plants, etc. A paper on Pemphiffiis 

 tcsscUata, by Miss Edith M. Patch (pp. 35, 36), calls attention to the fact that 

 the life cycle of comparatively few of the species belonging to the genus Pem- 

 phigus is known. It is shown that the Pemphigus common upon the leaves of 

 Acer (laHycarpum from early spring to mid-July are hatched from the eggs of 

 P. tessellala deposited upon the maple trunk, as previously noted (E. S. R., 20, 

 p. 856). The Economic Status of the House Fly is discussed in a paper by E. P. 

 Felt (pp. 39^4). 



89616— No. 1— (JO 5 



