INTRODUCTION. 
xlix 
and is very generally dispersed over the British Islands from its arrival in May until its departure in 
September. 
46. Caprimulgus ruficollis ...... ... Vol. II. PI. II. 
Red-necked Goat-sucker. 
An inhabitant of Spain, North Africa, and Palestine, which has once appeared in our islands. 
Family CYPSELIDiE. 
The Swifts have been divided into two subfamilies, CypselincB and Ch<stunncB. They are found both in 
the New and the Old World. Two of the CypselincB occur in Britain ; and one of the ChcetunnoB having in 
a single instance been killed here, it becomes necessary to include it in the list of our avifauna. 
Genus Cypselus. 
47. Cypselus apus ............ Vol. II. PI. III. 
Swift. 
Arrives in May and departs southward in August or the early part of September, and is therefore a true 
migrant. \ 
48. Cypselus melba ............ Vol. II. PI. IV. 
Alpine Swift. 
A common migrant on the continent of Europe, particularly in its central and southern parts ; it also 
inhabits Africa and India, and is an accidental visitor to Britain. 
Genus CuiETURA. 
The members of this genus are generally dispersed over America ; nor are they absent from Asia, Africa, 
or Australia. They have been divided into several subgenera ; that of Hlrundapus has been assigned to the 
single species which in a solitary instance has found its way to Britain ; hut I retain it under the older term 
by which it is more generally known. 
o 
