12 NORTH AMERICAN BATS II. ALLEN. 



Ciives, attics, aiul old tree trunks and those whifb are caught han}i,ing 

 from the smaller branches and twigs of trees and bushes. 



Bristles (seta') usually surmount warts (vci'ruca"). They are best de- 

 veloped on the lace of Mohssi, though they may be found in the groui) 

 last named on the u^^per surface of the interfemoral membrane. The 

 very long haiis of the sides of the muzzle, which are so conspicuous in 

 many of the small mammals of other orders, notably the llodentia and 

 Carnivora are absent. Tlui best examples are met with in Vcspeytilio 

 ami Chocronyvtet'is. Fringes of bristles adorn the margins of the toes 

 in Molossi. 



In describing bats in this manner the attention which has been given 

 to the details of the coloring and the markings on membranes require 

 an exact use of terms. 



When Iiair arises from the membrane it will be seen that the clumps 

 follow the directions of the trabecuhe and are detected in the trans- 

 lucent wing as minute black dots arranged in rows. These must not 

 be confounded with i)igment spots which dot the naked spaces of the 

 wing in some species. 



GLANDS. 



The skin glands are best developed on the sides of the fiice directly 

 back of the muzzle. In Molossi a large, median, coarse sebaceous gland 

 lies on the under surface of the neck. It is best developed in the male. 

 The mammiTe are large during the lactating. period Mhen the nipples are 

 projecting and the aveolar space naked. At other times the nipple 

 disappears and the gland is reduced to the smallest possible propor- 

 tions. In 8acG<ypteryx and its allies the wing membrane above the an- 

 terior extremity is furnished with a sack which is lined with folds which 

 yield a fetid secretion. The position and size of this sack furnish ex- 

 cellent characters to distinguish genera as well as sexes of individuals. 



COLORATION. 



It is necessary to state that the colors for the most part are described 

 from alcoholic specimens which have been removed from the si)irit and 

 permitted to dry. Mr. F. W. True writes in the Smithsonian Report 

 for 1888 that alcohol disturbs the color scheme of a mammal. The 

 character of alcohol is not especially here named and the remark is 

 undoubtedly correct for specimens which have been preserved in wood 

 spirit. However, none of the specimens used for study have been pre- 

 served in other than commercial alcohol Avhicli has been variously 

 diluted with water. I have observed no diflerences of the kind named 

 between the few living individuals I have seen, the fur of the dried 

 skin prepared in the usual way with arsenic and in skins dried after 

 prolonged immersion in commercial spirit. It must also be remembered 

 that since all the material available for my study has been i>reserved 



