346 EXPERIMENT STATION EECOED. 



mixture. This claim was not sustained. Moreover, Cucasa was found to 

 deteriorate rapidly with age. 



A silver nitrate emulsion discovered in France was tested later in tlie year on 

 a small scale in comparison with Bordeaux mixture with results so favorable 

 as to warrant repetition on a larger scale. 



ECONOMIC ZOOLOGY— ENTOMOLOGY. 



The races of Indian rats, R. E. Lloyd {.Rec. Indian Mus., 3 {1909), No. 1, 

 pp. lO-'t, pis. 7, figs. 11). — An inquiry supplementary to the investigation of 

 plague, and dealing with the origin of races from sports. 



Reproduction in the brown rat (Mus norweg'icus), N. Miller {Amer. Nat., 

 //5 (1911), No. 538, pp. 623-635, figs. 2).—" The brown rat breeds in every month 

 of the year. The gestation period is 23i to 25i days. The number of young 

 per litter varies from 6 to 19 with an average of between 10 and 11. Five or 6 

 litters may be reared by a single pair in a year. . . . Brown rats in captivity 

 eat almost 50 per cent of their young at birth. Most of the young eaten, if not 

 all, are eaten by the females. Full growth is attained not under 18 mouths. 

 Sexual maturity is reached at least by the end of the fourth month in both 

 sexes." 



The birds of North and Middle America, R. Ridgway {U. S. Nat. Mus. 

 Bui. 50, pt. 5, 1911, pp. XXIII +859, pis. 33).— This part (E. S. R., 19, p. 251) 

 deals with the birds of the families Ptei'optochidse or tapaculos, Formicariidse 

 or antbirds, Furnariidfe or ovenbirds, Dendrocolaptidoe or woodhewers, Tro- 

 chilidse or humming birds, Michopodidae or swifts, and Trogonidse or trogons. 



The relation of birds to an insect outbreak in northern California during 

 the spring and summer of 1911, H. C. Bryant (Condor, 13 {1911), No. 6, 

 pp. 195-208, figs. 4)- — This is a report of investigations conducted during an 

 outbreak of a plague of caterpillars of the nymphalid butterfly Eugonia cali- 

 fornica which occurred in the northern counties of California, especially in 

 Siskiyou County, during the spring and summer of 1911. The caterpillar feeds 

 upon snow brush (Ceanothus cordulatus) or buck brush {C. velutinus). 



Five species of birds were found to feed on E. calif ornica, viz, the Brewer 

 blackbird {Euphagus cyanocephalus) , western meadowlark {Sturnella neg- 

 lecta), western kingbird {Tyrannus verticalis), blue-fronted jay (Cyanocitta 

 stelleri frontalis), and Say phoebe {Sayornis sayus). The Brewer blackbird 

 was found to be the most efficient check both on account of numbers and food 

 habits, taking 95 per cent of all the butterflies eaten by birds. An examination 

 of 13 stomachs of the red-winged blackbird (Agelaius phoeniceiis, subspecies?) 

 showed over 93 per cent of its food to be vegetable matter, thus bringing out 

 the vast difference in food habits between this bird and the Brewer blackbird, 

 S3 per cent of whose food was animal matter. 



Eugonia californica in the butterfly stage, probably on account of its large 

 size, was not eaten by any species of bird smaller than the Say phoebe. The 

 smaller birds probably had a more intimate relation to the outbreak when the 

 insect was in the larval and pupal stage. 



" The data collected show of what value birds may be in the checking of an 

 insect outbreak rather than their value in the prevention of an outbreak." 



Entomology in the West Indies (West Indian Bui., 11 {1911), No. },, pp. 

 282-317). — A summary of the entomological work undertaken by the Imperial 

 Department of Agriculture from October 1, 1898, to March 31, 1911. 



Nature sketches in Temperate America, J. L. Hancock {Chicago, 1911, 

 pp. XVIII+451, pis. 12, figs. 215; rev. in Auk, 28 {1911), No. If, pp. 498, 499)-— 

 Under sectional headmgs, the author deals with (1) Evolution and Natural 



