34 



2. A Monograph of the Genus Lasiurus. 

 By Robert F. Tomes, Esq.. 



The object of the present memoir is rather to enumerate and de- 

 scribe all the species at present arranged under the above name, than 

 to enter into the claims of the group to be considered as a distinct 

 genus. 



An attempt is also made to give a tolerably correct synonymy ; 

 but there are so many descriptions which appear to refer to varieties 

 only, as to render this part of the work by no means easy, and not 

 altogether satisfactory. Attached to the account given of the first 

 species on the list — Lasiurus noveboracensis — will be seen a rather 

 voluminous list of synonyms ; and it may appear as if undue regard 

 had been paid to the labours of other writers, in thus reducing to one 

 species what has by them been considered as constituting at least 

 six. But in the examination of a large number of examples, I have 

 felt myself quite unable to come to any other conclusion than the 

 one here given. The various descriptions apply to the same species 

 under the influence of the climate of different degrees of latitude. 

 Thus the Vespertilio noveboracensis answers well to the account 

 given of it in its proper locality ; but as we proceed southward, we 

 find that a Bat occurs, having precisely the same form and size, but 

 differing somewhat in the colouring of the fur ; and this difference 

 continues to increase until we reach the tropical parts of America, 

 where a bright ferruginous colour completely supersedes the original 

 hoary -brown, or, as it might not improperly be called, roan-colour. 



At various localities it has been met with by travellers, and the 

 colour of the fur varying with most of them, has given rise to the 

 great multiplicity of names. A large series has passed under review 

 whilst preparing this paper, and the most exact and rigorous exami- 

 nation, both externally and internally, has failed to afford any mate- 

 rial difference, beyond that of colour. 



I have already referred this to the effect of climate ; but it is ne- 

 cessary to add, that the colour of the fur is so capricious, even in 

 the temperate parts of North America, that Major Le Conte, when 

 describing specimens from the vicinity of Philadelphia, found the 

 varieties so perplexing, that he could give no very definite descrip- 

 tion. 



However, it may be stated, that generally the North American 

 examples are some mixture of brown or rufous, thickly sprinkled 

 with white, giving a hoary appearance ; whilst those from Tropical 

 America are almost uniformly of a bright ferruginous hue, without 

 any mixture of white. 



1. Lasiurus noveboracensis, Erxl. 



Vespertilio noveboracensis, Erxl. Syst. Reg. Anim. p. 155, 1777 ; 

 Harl. Faun. Amer. p. 20, 1825 ; Godm. Amer. Nat. Hist. i. p. 50, 

 1826 ; Fisch. Synop. Mam. p. 114, 1829 ; Coop. Ann. Lye. N. H. 

 New York, iv. p. 57, 1837 ; Le Conte, Proc. Acad. Nat. Sci. Philad. 

 1855. 



