642 NIGHTJAR 



the east and Fernando Po on the west, and is reported to have 

 occurred in Madagascar and Socotra. In this the remigial streamers 

 do not lose their barbs, and as a few of the next quills are also to 

 some extent elongated, the bird, when flying, is said to look as 

 though it had four wings. Specimens of both are rare in collections, 

 and no traveller seems to have had the opportunity of studying the 

 habits of either so as to suggest a reason for this marvellous sexual 

 development, though the late Mr. Joseph Gedge, who accompanied 

 Sir Samuel Baker's expedition to the Soudan, on one occasion 

 observed a Macrodipteryx squatting on the ground with its long 

 remiges erected perpendicularly, and the accompanying figure is from 

 a sketch sent by him to his friend Mr. Marlborough Pryor. 



The second group of Caprimulginse, those which are but poorly 

 or not at all furnished with rictal bristles, contains about five genera, 

 of which there is here only room to particularize Lyncornis of the 

 Old World and Chordiles of the New. The species of the former 

 are remarkable for the tuft of feathers which springs from each side 

 of the head, above and behind the ears, so as to give the bird an 

 appearance like some of the " Horned " OWLS those of the genus 

 Scops, for example ; and remarkable as it is to find certain forms of 

 two Families, so distinct as are the Strigidte and the Caprimulgidse, 

 resembling each other in this singular external feature, it is yet 

 more remarkable to note that in some groups of the latter, as in 

 some of the former, a very curious kind of DIMORPHISM takes place. 

 In either case this has been frequently asserted to be sexual, but on 

 that point doubt may be fairly entertained. Certain it is that in some 

 groups of Nightjars, as in some groups of Owls, individuals of the 

 same species are found in plumage of two entirely different hues 

 rufous and grey. The only explanation as yet offered of this fact is 

 that the difference is sexual, but, as just hinted, evidence to that effect 

 is conflicting. It must not, however, be supposed that this common 

 feature, any more than that of the existence of tufted forms in each 

 group, indicates any close relationship between them. The resem- 

 blances may be due to the same causes, concerning which future 

 observers may possibly enlighten us, but at present we must regard 

 them as analogies, not homologies. The species of Lyncornis inhabit 

 the Malay countries, one, however, occurring in Burma and India. 

 Of Chordiles the best-known species is the Night-hawk of North 

 America, C. virginianus or popetue, which has a wide range from 

 Canada to Brazil. Others are found in the Antilles and in South 

 America. 



We have next to consider the birds forming the genus Podargus 

 and those allied to it, whether they be regarded as a distinct Family, 

 or as a subfamily of Caprimulgidaz. As above stated, they have 

 feet constructed as those of Birds normally are, and their sternum 

 seems to present the constant though comparatively trivial difference 



