308 THE ZOOLOGIST. 



Borassus grows ; about a dozen pairs commonly resorting to the 

 same tree, and attaching their nests to the upper surface of the 

 drooping fan-like fronds, protected by overhanging fronds above. 

 Affixed by the glutinous secretion to a plait of the frond, the rest 

 of the nest does not (as in other Swifts) appear to be cemented by 

 this substance, but is a closely-felted mass of silk-cotton (the 

 pappus of the Bombax heptapliyllum), forming a neat cup of con- 

 siderable strength, and lined with feathers. Except in size and 

 mode of attachment, it is indeed remarkably like the nests of the 

 generality of TrochiUdce.* The eggs I have not seen. The palm 

 selected for their abode is conspicuously indicated by the birds 

 perpetually keeping about it, and ever and anon one or more of 

 them entering or leaving the recesses of its dense head of foliage, 

 sharply twittering as they fly, in their rapid, irregular, and vacil- 

 lating course, sustained by much action of the wings. Not 

 unfrequently the same palm is tenanted by a busy assemblage of 

 Bayas (Ploceus), with their pendant retort-like nests waving in the 

 breeze. 



Mr. Gosse has lately described a species of very similar habits 

 in Jamaica, which he makes a genus of, and designates Tachornis 

 phamicohia. The chief difierence from Cypselus seems to be that 

 the ossification of the sternum and its ridge continues permanently 

 incomplete (as in the Collocalice) , denoting a general weaker 

 structure. In the Indian Palm Swift such is not the case. The 

 latter species does not appear to have been observed by Mr. 

 Hodgson in Nepal, but to the eastward we have seen it from 

 Arracan (Ramree). 



* Indeed the Hummiug-bu'ds affix their nests to a single twig, vertical or 

 horizontal, according to tlie species ; and Mr. Gosse, in his description of the 

 nest of Trochilus polytmus, notices "some viscous substance, probably 

 saliva, evidently apjilied after the web was placed," alluding to a covering of 

 spiders' webs "crossed and recrossed in every du'ection" over the outside of 

 the fabric. Hence it seems not improbable that species of Trochilidee may 

 yet be discovered to attach the nest to a flat surface, like the Cypselidce, if 

 indeed they do not all use the same glutinous secretion to make the first 

 rudiments of it adhere. These diminutive birds sleep roosting, as do probably 

 the Macro])teryx genus of the Cyj^selidcc, and do not put the head beneath 

 the wing, like most other birds. Neither probably do the Cypselidce, as also 

 the Trogonidce and Cajprimulgidcc. The lengthened white eggs of the 

 Cypselidce and TrochiUdce present a further similarity between the two 

 families. 



