LIFE HISTORY OF DESMOGNATHUS FUSCA. 255 



where the first few days of the larval life are spent. The young 

 larvae, however, soon reach shallow running water where they 

 remain for nearly a year, after which they come out of the water 

 to live the terrestrial adult life of the species. The presence of 

 aquatic as well as terrestrial insect forms in the stomachs of 

 adult Desmognathus shows, however, that even the adults are 

 by no means absolutely terrestrial, but, so far as my own obser- 

 vations and those reported by others go, the adults confine their 

 aquatic excursions to very shallow water, and they are seldom 

 found in the water at all unless driven there. 



Apparently, the ideal environmental conditions for Desmog- 

 nathus fusca, as deduced from a study of those localities in which 

 they occur in the greatest abundance, are those afforded by the 

 banks of well shaded streams of shallow, perennially running 

 water. In such places they may usually be found under every 

 stick and stone and fallen log at or below the water level, while 

 the soft earth is riddled with burrows, often, it is true, the work 

 of earthworms or of other animals, but utilized as convenient 

 lurking places for Desmognathus; for the adult Desmognathus is, 

 in the day time, at least, thigmotropic, and will even take refuge 

 in a bottle left lying on the surface of the soil exposed to the 

 light, usually orienting the body with the head toward the 

 mouth of the bottle. Desmognathus has the power to make its 

 own burrows, as it will demonstrate, sooner or later, when 

 isolated in a terrarium w r hich affords no other suitable means of 

 protection. In one case in particular which came under my 

 observation, two individuals were accidentally set aside in a 

 terrarium which was supposed to contain no specimens. Over 

 a year afterwards it was found that these animals were still 

 living in this terrarium under almost perfectly dry conditions. 

 In the soil were many well formed burrows, within which the 

 specimens, which were kept for some time after they were 

 discovered, remained, often completely concealed, but at times 

 with the head protruding from the entrance to the burrow. 



Under natural conditions the crevices and burrows inhabited 

 by Desmognathus are, of course, very moist, and I have usually 

 been able to demonstrate, by following them carefully through 

 their windings and branchings, a connection with the water of 

 then eighboring brook. 



