GALEEIDA THEKL^ DEICHLEBI 267 



To Baron v. Erlanger belongs the merit of having first pointed 

 out that the small-billed isabelline-coloured Crested Lark of Southern 

 Algeria and Tunisia cannot rightly be referred to Bonaparte's 

 Galerida isahellina, by which name it has of recent years generally 

 been known. 



The Lark described by Bonaparte (Conspectus, i, 1850, p. 245) 

 was stated to be a pale-coloured bird from Nubia, with a bill like 

 that of the Crested Larks, which presumably means like that of the 

 common Crested Lark of Europe. 



From Nubia, in fact, we have Crested Larks which agree with 

 Bonaparte's description, being rather large pale-coloured birds, with 

 long bills, and with short bastard primaries, birds evidently belonging to 

 the G. cristata group, whereas the short-billed Crested Larks of South 

 Algeria and South Tunisia distinctly belong to the G. theklce group. 



The fact that Bonaparte's name of G. isahellina cannot apply 

 to these Algerian and Tunisian birds being clearly established, it 

 behoves us to look about and see if any other existing name be 

 applicable. 



The only one which might perhaps be so appears to be that of 

 G. liifea (Brehm), which according to the description given applies to 

 a short-billed bird, with a long bastard primary, evidently a bird 

 belonging to the Theklce group. 



Owing to the uncertainty, however, of what Brehm's G. lutea 

 really was, and not having been able to see any examples of it, 

 I cannot, for the present at any rate, do otherwise than accept 

 Erlanger's name of G. t. deicJileri, and refer the isabelline small-billed 

 Crested Lark of Tunisia to it. 



This pale isabelline form, as already stated, inhabits the inland 

 semi-desert districts of the south of the Regency. Its furthest 

 northern limit may be said to be the country lying to the west of 

 Gafsa, though examples from those parts are not quite so pale in 

 colour as those found further south. Specimens, indeed, from districts 

 south of the Chott Djerid are remarkably light-coloured, their pale 

 hues harmonising admirably with those of the sandy wastes which 

 form their home. 



Further east or south-east, where the country is more rocky and 

 broken, the rufous form, G. t. Carolina, takes the place of the present 

 one. 



I have no specimens of G. t. deichleri from the Algerian Sahara, 

 but the form is said to occur there. 



