of Selborne 153 



any naturalist to make his remarks. This I have often 

 taken notice of, tliat several holes of different depths are 

 left unfinished at the end of summer. To imagine that 

 these beginnings were intentionally made in order to be in 

 the greater forwardness for next spring, is allowing per- 

 haps too much foresight and reni7n p7ydc7iiia to a sim])]e 

 bird. May not the cause of these latebrce being left 

 unfinished arise from their meeting in those places with 

 strata too harsh, hard, and solid, for their purpose, which 

 they relinquish, and go to a fresh spot that works more 

 freely? C3r may they not in other places fall in with a 

 soil as much too loose and mouldering, liable to flounder, 

 and threatening to overwhelm them and their labours ? 



One thing is remarkable — that, after some years, the 

 old holes are forsaken and new ones bored ; perhaps 

 because the old habitations grow foul and fetid from 

 long use, or because they may so abound with fleas as to 

 become untenable. This species of swallow moreover is 

 strangely annoyed with fleas : and we have seen fleas, 

 bed-fleas {pulex irritans), sw^arming at the mouths of 

 these holes, like bees upon the stools of their hives. 



The following circumstance should by no means be 

 omitted — that these birds do not make use of their 

 caverns by way of hyhemaada, as might be expected ; 

 since banks so perforated have been dug out with care 

 in the winter, when nothing was found but empty nests. 



The sand-martin arrives much about the same time 

 with the swallow, and lays, as she does, from four to six 

 white eggs. But as this species is c?yptoga?ne, carrying on 

 the business of nidification, incubation, and the support 

 of its young in the dark, it would not be so easy to 

 ascertain the time of breeding, were it not for the coming 

 forth of the broods, which appear much about the time, 

 or rather somewhat earlier than those of the swallow. 

 The nestlings are supported in common like those of 

 their congeners, with gnats and other small insects ; and 

 sometimes they are fed with Ubellula:. (dragon-flies) almost 

 as long as themselves. In the last week in June we have 

 seen a row of these sitting on a rail near a great pool as 

 perchers ; and so young and helpless, as easily to be 



