A MONOGRAPH OF THi: BaTS OF NORTH AMERICA. 147 



Florida aia n<»t only smaller in «ize than those from the North, but are 

 much deeper in color; the fur is generally tipped with ash. 



The extent to which hair is distributed ov^er the skin expanse is 

 subject to cousiderablc variation. It is scantily present over tlie dor- 

 sum of the interfemoral membrane and the ventral region of the forearm 

 in all tlie specimens (three in number) which have been collected in 

 California. In tliis particular such specimens resemble the parts as 

 found in D.cf/rt, (rervais and J), crfregia, Peters. It is i)ossible that the 

 Mexican A. frantzii may range northward as far as California. In 

 specimen No. 1421 from Massachusetts, in the Museum of Comparative 

 Zo«31ogy, the hair is restricted in almost precisely the same manner as 

 in the western and neotropical varieties. It is interesting to notice the 

 persistence of the minute tufts of hair on the first and fifth metacarpal 

 elements. These appear early in the individual, while the other growths 

 appear late, and are hence subject to a greater range of variation. 

 The size of the post-calcaneal lobule varies, and in some specimens it is 

 absent. Dobson states that it is always absent. The prebrachial mem- 

 brane is as a rule ample, but it may end on the radius at a point at the 

 beginning of the distal fourth of the radius. Wheu the membrane is 

 scant the auricle is thick and well set. It is suggestive that in the 

 ]Molossi when the auricle is thick and leathery the autibrachial mem- 

 brane is also small. 



It is evident from the above account that extended series from the 

 entire continent will be necessary before the observer can determine 

 the \alidity of sjiecies which have been described from Mexico and 

 South America. From the material at my disposal I prefer to accept 

 but two red bats in the United States, A. noveljoraeensis and A. teliotis, 

 though holding as probable that a distinct species may be discovered 

 in Florida. The figure drawn by M. Duges (PI. xxvii, fig, 2) exhibits 

 the auricle bordered by a broad margin of a contrasting shade to that 

 of the interior, as in A. cincrea and the tragus not incurved. It is 

 probable that the fur conceals the external basal lobe, as here repre- 

 sented. 



Maj. Le Conte mentions having met with an entirely white form, the 

 bases of the hair alone being dailc. It was probably an albino. 



In a specimen from Cambridge, Mass., in the collection from Mr. G. 

 S. Miller, jr., the internal basil lobe ends abruptly at the outer end of 

 the internal basil ridge, and is sparsely covered with hair on the con- 

 cha! surface. 



So acute an observer as Mr. J. A. Allen believed, in 1809 (Bull. Mus. 

 Comp. Zool., 18G9, 14.3j, that the red and hoary bat may yet prove to 

 be one and the same species. In this opinion I can not concur. 



Membranes. — The membranes are attached almost to the back of the 

 trunk. The prebrachium forms a ridge at the side of the neck over the 

 occipito-pollical nnisde. Tlie thumb is disposed to be drawn palmad 

 by tlic trachimof this mnscle, but ton nuu-h less degree than in s])ecies 

 of Phyllostomidie. The thumb callosity is not wider than the adjacent 



