CAPEIMULGUS ^GYPTITJS ISABELLINTJS 37 



ence between the two forms, and merely observes that Lichtenstein's 

 name of C. cBgijptius is not appropriate, because there are other 

 Nightjars to be found in Egypt. Under the circumstances, however, 

 and considering what I have stated above of Temminck's plate and 

 description being appHcable to an isabeUine-coloured bird, I think the 

 name of C. isabeUinns must stand subspecifically, and the Tunisian 

 Desert-Nightjar be referred to it. 



In addition to the difference in the general coloration of the two 

 forms, there would seem to be much closer barring in the grey form 

 than in the isabelline form, particularly on the sides of the body and 

 under wing-coverts, this barring in Tunisian examples being nearly 

 obsolete. 



The wing measurement in the two forms does not seem to differ 

 appreciably, that of males being about 7'70 inches, and that of females 

 about 8 inches. 



This pale Nightjar occurs in the more southern districts of Tunisia, 

 but is not to be found, except as a straggler, north of the Atlas. In 

 Algeria it is also to be met with south of those mountains, and Dr. 

 Koenig found it not at all uncommon in the neighbourhood of Biskra 

 (J. f. 0. 1895, p. 178). North of the Atlas he never met with the 

 species, and Loche is no doubt wrong when he speaks of it as being 

 found in the wooded districts of Constantino. 



I have no note of the occurrence of this Nightjar either in Marocco 

 or in Tripoli, but should think that it certainly occurs in the latter 

 country, and possibly also in the former. Although the species is no 

 doubt distinctly a desert one, it occurs as a straggler from time to 

 time north of the Mediterranean, and I have myself obtained an 

 example of it in Sicily (Ibis, 1899, p. 475), from which island it had 

 previously been recorded twice. Examples of the species have also 

 been obtained in Malta, and even as far north as England and 

 Heligoland. 



In Tunisia this pale Nightjar can hardly be called common, but at 

 the same time it is not by any means rare. I have specimens of it 

 from the neighbourhood of Gafsa, Tozer, and Oglet-Zelles, all obtained 

 during the spring months. Apparently it arrives in the Eegency 

 about the middle of March, nests there, and departs again in the 

 autumn. I know of no instance of its being met with in Tunisia 

 during the winter. 



In its general habits this Nightjar does not seem to differ from 



