OF SELBORNE. 301 



bed fleas ( pulex irritans ), swarming at the 

 mouths of these holes, like bees on 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 

 hybernacula, 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 cryptogame, 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 in^ 

 sects ; and sometimes they are fed with 



