ECOLOGY. 361 



the soil is placed in an apparatus similar to that devised by Moczarski 

 (described by Holdhous, 1910) . All the animals removed from the soil 

 by this means are added to those removed after sifting in order to ob- 

 tain the total. 



Nearly all the anunal life in the soil studied is limited to the first 

 2.5 cm. This is true of the different communities and shows no precise 

 correla-tion with temperature, moisture, fineness, or ignition-loss. In 

 the yellow pine-bearberry community the bare gravel contains Acarina 

 in comparatively small numbers, but the duff covered with bearberry 

 contains an abundance of Collemhola, as well as mites. At the other 

 extreme, the wet fine silt along the brook bank is rich in earthworms 

 and insects, both larvae and adults, in addition to numerous Acarina 

 and Collemhola, while the soil of the fir forest contains large num- 

 bers of mites, Collemhola, Chilapoda, Diplopoda, Pseudoscorpions, and 

 insects, together with occasional earthworms. The other quadrat 

 stations are more or less intermediate between those given. The sea- 

 sonal changes in the species and the number of individuals are being 

 followed in detail. The particular factors involved in the control 

 of various species are being determined by removing species peculiar to 

 one area to other quadrats and keeping them under observation in 

 screen vivaria. 



Faunal Studies in Mixed Prairie and Bad Lands, hy F. E. Clements and 



C. T. Vorhies. 



A special study has been made throughout the Bad Land expedition 

 of the fauna of the mixed-prairie climax and the characteristic Bad 

 Lands m it. The Bad Lands afford a bewildering number of suc- 

 cessional stages and thus permit ready comparison with the fauna of 

 the biotic cliamx. Some attention was paid to practically all the ani- 

 mal groups, but the study was concentrated upon mammals, birds, and 

 insects. A list of species found was made for each region and for each 

 Bad Land locaHty, and some account was taken of their relative abun- 

 dance. It was recognized that, in a single climax association at least, 

 the basic control of the animal population must be exerted by the plants, 

 and hence the chief study was devoted to the correlations involving 

 food, shelter, cover, and materials. Among the insects, many oligo- 

 tropic and monotropic fonns were found, but the birds and mammals 

 were able to adapt themselves more easily to changing vegetation. 

 This ability was found to be most marked iu the prairie-dog, especially 

 Cynomys leucurus, which was found almost equally at home in a pure 

 consocies of Atriplex nuttallii, in sagebrush, in mixed sagebrush and 

 prau'ie, and in various communities of the mixed prairie. A study of 

 special interest dealt with the material used by ground birds for the 

 different portions of their nests. In all cases this was found to be de- 

 termined by the natui'e of the community and by the season, as would 



