178 ANIMAL LIFE OF CARLSBAD CAVERN 



matter in the stomach and intestines, perhaps specks 

 of insect remains from bat droppings, or spores of the 

 mold plants, or mere particles of decaying vegetable 

 matter washed in long ago from the surface above, at 

 best a meager diet that through the long ages might 

 well have modified the bodies of these insects to their 

 present attenuated and ethereal appearance. 



The cave mice caught in the lower levels of the cave 

 had been feeding to a considerable extent on these in- 

 sects, and some of their stomachs contained nothing 

 else. Here this mouse is supposedly the principal 

 food of the larger ring-tail, and thus these obscure and 

 far-away insects contribute in a humble and indirect 

 way towards converting earthy matter into higher and 

 higher types, each dependent upon lower forms, and 

 each more useful in our scale of estimates. 



Blow Flies. Down one hundred and seventy feet 

 below the surface of the ground, in the first large room 

 of the cave, the slow, heavy buzzing of a fly was heard 

 on several occasions, but as the flies could not be de- 

 tected even by the light of a powerful gasoline lantern, 

 the insect net was useless. The deep-toned buzzing 

 suggested a blue-bottle or blow-fly, so meat bait was 

 tried. A freshly killed cottontail rabbit and a wood rat 

 were cut up and pieces distributed at strategic spots. 

 Within an hour two large blue blow-flies (Calliphora 

 vomiteria nigribarba Shannon) were captured near the 

 bottom of the east shaft, or bucket entrance to the cave. 

 Others were seen on the bait, and one was found laying 

 eggs in the meat. This was in total darkness, as the 

 old shaft, not in use, was covered, and practically no 



