194 



SCIENCE 



[N. S. Vol. XLIX. No. 1260 



tions by the author and her associates. In 

 connection with habits the lauthor states (p. 

 232) "The habits of our California bats are, 

 unfortunately, but little known. The time 

 and extent of the breeding season, migration 

 and hibernation, the choice of diurnal re- 

 treats, and favorite feeding grounds, the meth- 

 ods of securing and devouring prey, the nature 

 of the food, the economic value of bats — these 

 are only a few of the many points on which 

 data are as yet almost wholly lacking." 



In connection with breeding habits and ene- 

 mies, no mention is made of the interesting 

 difference in numbers of young between crev- 

 ice-inhabiting bats and certain tree-inhabiting 

 species. As is well known Nycteris cinereus 

 and Nycteris horealis, tree inhabiting forms, 

 have from two to four young, while crevice 

 and cave-inhabiting species have only one or 

 two. As implied by ISTelson^ this seems to be 

 due to the increased risk from the habitat re- 

 lations of the tree-living forms. An aug- 

 mented mortality proba;bly results also from 

 the migratory habit of Nycteris. 



That bats deserve protection for their yeo- 

 man service in destroying insects goes without 

 saying. It seems probable, however, that 

 Campbell's estimate of the value of their work 

 in Texas in destroying mosquitoes and thereby 

 reducing malaria, quoted by Mrs. Grinnell on 

 pages 238-239, is exaggerated. Stomach ex- 

 aminations of Nyctinomus mexicanus have 

 shown many insects, but mosquitoes only 

 rarely. 2 



The most adequate statement regarding the 

 relation of bats to geographical distribution 

 which has been seen by the reviewer is made 

 by Mrs. Grinnell (pp. 242, 243), who empha- 

 sizes the fact that " conditions of temperature 

 and humidity limit the distribution of bats as 

 strictly as they do that of other groups of 

 mammals. In California there is not a single 

 .obvious barrier to the distribution of any 

 species of bat; yet not one of the tliirty-one 

 forms inhaibiting the state has been found to 



1 National Geographic Magazine, May, 1918, p. 

 491. 



2 See E. W. Nelson, National Geographic Maga- 

 eine, May, 1918, p. 492. 



be distributed uniformly throughout the entire 

 area." 



A study of the dates of capture of Nycteris 

 horealis teliotis leads, according to our author, 

 to the inference that "the sexes separate dur- 

 ing the smnmer months, the females remain- 

 ing in the Lower Sonoran zone, while the 

 males migTate into the Upper Sonoran and 

 Transition zones (p. 326)." After reference 

 to a similar withdrawal' from the breeding 

 grounds by the males of certain species of 

 birds, Mrs. Grinnell suggests that " Their de- 

 parture relieves congestion in the nesting 

 area and leaves a greater food supply for the 

 females and young." In the case of red bats 

 in California, however, one can not readily 

 concede the implications either of congestion 

 in their breeding area or the necessity, with 

 an insectivorous species of the sort, for a 

 greater food supply in summer; but the dis- 

 covei-y of the separation of the sexes as noted, 

 if confirmed with the acquisition of more 

 material, is most interesting whatever its ex- 

 XJlanation. 



There are no descriptions of new forms. 

 N'ew locality records are published for nearly 

 every California species and subspecies. Sub- 

 species aliipetens H. W. Grinnell of Myotis 

 is here referred to species lucifugus rather 

 than yumanensis as originally described. 

 Myotis lucifugus alasceiisis Miller is for the 

 first time recorded from California, a speci- 

 men having been taken at Eureka. Definite 

 records of occurrence in California of Myotis 

 lucifugus interior Miller are also published 

 for the first time. Antrozous pacificus Mer- 

 riam is accorded full specific rank instead of 

 being regarded as a subspecies of pallidum. 



The paper is generously illustrated with 

 half tones and maps. Life studies of several 

 species appear, and comparisons of dorsal 

 and lateral outlines of bat crania are made 

 possible by an extensive series of enlarge- 

 m.ents. A few well executed line drawings 

 show particular external characteristics of 

 bats, and clear maps indicate the geographic 

 ranges within California of all tlie forms con- 

 sidered. 



