MODIFICATION OF THE BEHAVIOR OF LAND ANI- 

 MALS BY CONTACT WITH AIR OF HIGH 

 EVAPORATING POWER 



VICTOR E. SHELFORD 



Hull Zoological Laboratory, University of Chicago 



I. INTRODUCTION 



The rapid modification noted in the case of fishes, by the author 

 and Dr. W. C. Allee is likewise shown by various land Amphi- 

 bians and Arthropods, used in experiments designed to test 

 the sensibility of different terrestrial animals to variations in 

 evaporating power of air. Some animals of supposedly lower 

 organization than the fishes, showed modifications similar in 



OH ri T"rJ Ot~ PT* 



II. MATERIAL AND METHOD 



The following species were studied: the yellow margined 

 milliped (Fontaria corrugate Wood), ground beetles (two species 

 of Pterostichus) , the wood frog {Rana sylvatica LeC), the red 

 backed salamander (Plethodon cinereus Gr.) — all fro'm moist 

 forest habitats; and the common toad (Bufo lentiginosa), the 

 small digger wasp (Microbembex monodonta Say), the bronze 

 tiger beetle (Cicindela lecontei Hald), and the sand spiders 

 (Geolycosa wrighti Em and pikei Marx) — all from dry sand 

 dunes. 



The animals were put into small cages across which air was 

 forced through three narrow slits. The ground plan of the cages 

 is indicated in Fig. 1. The covers of the cages were of glass, 

 the fronts opposite the slits of screen. Gradients of evaporating 

 power were secured by passing air of different relative humidities, 

 or different temperatures, or by passing it at different velocities 

 across the different thirds. Thfe device for thus controlling the 

 rate of evaporation was designed by the writer and Prof. E. O. 

 Deere of Bethany College. The statistical and environmental 

 aspects of the one hundred experiments performed together with 

 details of the methods were published elsewhere (Biol. Bull., 

 June, 1913). Nearly seventy-five of the experiments were of 

 such a character as to bring out the modification phenomenon. 

 The tracings of the movements were drawn to a minute and 



