PLATE in 



Fig. 1. Portion of mesa at 3500 feet altitude near Dos Palmos Spring 

 on the desert slope of the Santa Rosa Mountains close to the upper 

 edge of the Lower Sonoran Zone; photograph taken May 27, 1908. In the 

 background, on the shaded slopes, are such Upper Sonoran shrubs as 

 juniper, Rhamnus, scrub-oak, and with them such birds as Aphelocoma c. 

 californica, Thryomanes h. charienturus, and Pipilo c. senicula. In the fore 

 ground Lower Sonoran vegetation predominates, with such birds as 

 Amphispiza b. deserticola, and Heleodytes b. couesi. Crossing this exact 



place was the lii f trap-- which produced in a single night -May 30, 



;?1) the following mammals: Perodipus a. agilis, Dipodomys m. simiolus, 

 Neotoma i. desertorum, Perognathus p. bangsi, Perognathus /. pallidum, 

 Peromyscus <. eremicus, Ammos'permophilus I. leucurus, and Notiosorex craw 

 fordi. other mammals taken in the vicinity were Sylvilagus b. cineras- 

 cens and Peromyscus b. rowleyi, thus showing the peculiar zonal overlap- 

 ping at this point. 



Pig. 2. Female Vireo vicinior on aest located 850 millimeters above the 

 ground in bush of Adenostoma fasciculatum. The nest is seen to be sup- 

 ported not only at several points in the rim, but by the stiff twigs at 

 sides and bottom. This was a species of extraordinarily limited range 

 si e p. 291). 



[406 



