TWINNING IN DASYPUS NOVEMCINCTUS 29 



Armadillos are pre-eminently insectivorous, although 

 not exclusively so. Insect-hunting is carried on at 

 night or at dawn and dusk. On warm nights one may 

 hear the sniffing and grunting noises made by the 

 armadillos as they root about among the dry leaves and 

 ground vegetation after the manner of hogs. In the 

 daytime they retire to their burrows, which are dug 

 to a depth of six or seven feet in the dry soil. An en- 

 larged chamber at the bottom is filled with dry leaves 

 into which the animal burrows for warmth in the 

 winter and during the cool spells of autumn and spring. 

 It is in the burrow that the young are born and reared. 



Mating occurs in October and the period of gestation 

 is between four and five months. The young are quite 

 advanced at birth and are able to walk about within 

 the first few hours. 



This incomplete account' of the natural history of 

 the armadillo is given here merely to enable the reader 

 to gain a slight acquaintance with the species that has 

 furnished the embryonic material forming the central 

 subject-matter of the present volume. In this place it 

 may not be inappropriate to extend to the modest and 

 retiring armadillo an acknowledgment of our indebted- 

 ness for much valuable data that no other animal could 

 have supplied. 



Our studies of the development of the armadillo 

 cover the whole range of stages from ovogenesis to 

 birth, with but one gap which, it is hoped, the near 

 future will see filled in. It has been impossible so far 



' A somewhat more adequate account of the natural history of this 

 species may be found in the following paper: H. H. Newman, American 

 Naturalist, XL VII (1913). 



