34 



2. A MONOGRAPH OF THE GeNUS LaSIURUS. 



By Robert f. Tomės, Esa. 



Tlie object of the present memoir is ratlier to enuraerate and de- 

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

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

 genus. 



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

 but there are so many descriptious \vhich 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 giveu of the first 

 species on the hst — Lasiurus novehoracensis — will be seen a rather 

 Toluminous hst of synonj'ms ; and it may appear as if undue regard 

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

 species what has by them been considered as coustituting 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 descriptious apply to the šame species 

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

 Thus the Vespertilio novehoracensis answers well to the account 

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

 find that a Bat occurs, having ])recisely the šame form and size, but 

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

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

 whcre a bright ferruc/inons colour completely supersedes the original 

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



At various locaUties it has been met -^vith by travellers, and the 

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

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

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

 nation, both externally and internally, has failed to aftbrd 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, wheu 

 describing specimens from the vicinity of Philadelphia, found the 

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

 tion. 



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

 examples are some mixture of brown or rufous, thickly spriukled 

 with white, giving a hoary appearance ; vvhilst those irom Tropical 

 America are ai most uniformly of a bright ferrugiuous hue, without 

 any mistnre of white. 



1. Lasiurus novehoracensis, Erxl. 



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

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

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

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

 1855. 



