xiv INTEODUCTIOX. 



Genus 10. PETROCIIELIDON. 



Nest. Bottle-.slia2:)ed. 



Eggs. White, spotted with rufous or brown. 



Two species afford an exception. P. nigricans \s> apparently a true Fetrochelidon in 

 form and style of colour ; hut it breeds in holes of trees, and makes a nest of straw and 

 feathers. It m ill probably be necessary to separate these Tree-building Swallows from 

 the Cliflf-building species, so as to include the two species in Hylochelidon, viz., 

 //. nigricans and H. timoriensis. 



Subfamily II. FSALIBOFBOCNIN^li. 



Genus 11. PSALIDOPROC^'E. 



These Hough-winged Swallows of Atrica are very Cypseline in their appearance and 

 ways, and lay two white eggs. Mr. Jackson found P. orientalis l)reeding in a cave, 

 somewhat after the manner of a Collocalia. P. pristoptera breeds in holes in the sides 

 of ravines. 



Geniis 12. STELGIDOPTEEYX. 



The American Rough-winged Swallows, on the other hand, l)uild in holes of Imnks, 

 like Sand-Martins, and, like the latter, lay several wliite eggs. 



