1. HTDEOCHELIDON. 5 



d'. Middle toe and claw shorter than exposed 

 culm en. 

 c". Bill strong, dectirvcd ; distance from 



the angle of the genys to the tip less 



than that to the gape ; the fourth pair 



of rectrices from the outside the 



longest 9. Angus, p. 136. 



(■/". Bill slender and long ; the distance 



from the angle of the genys longer 



than that to the gape; third pair of 



rectrices from the outside the longest. 10. MicRANotrs, p. 143. 

 e". Bill stout at the base, pointed ; culmen 



almost straight or slightly upcurved ; 



plumage pure white ; toes slender, the 



middle toe abnormally long ; webs 



deeply indented 11. Gygis, p. 149. 



1. HYDROCHELIDON. 



Type. 



Ilydrochelidon, Bote, Isis, 1822, p. .563 H. nigra. 



Viralva, Stephens, in S/icno^s Gen. Zool. xiii. pt. 1, p. 166 



(1826) H. nigra. 



Telodes, Kaup, Naturl. Sijst. p. 107 (1829) H. hybrida. 



Range. Temperate portions of North America ; Europe, Asia, 

 Africa, Australia, and New Zealand ; occasionally South America 

 in winter. Nesting in marshes, on tussocks or floating vegetation. 



Key to the Species. 



a. Black or dark grey below (summer plumage). 

 a'. Upper tail-coverts and tail white; under- 



parts black as far as the vent ; under wing- 

 coverts black ; coverts along carpal joint 



white to a considerable extent leucoptera, p. 6. 



b' . Upper tail-coverts and tail grey. 



a" . Bill orange-red (blood-red in life) ; chin 

 and sides of face white ; throat and breast 

 grey, passing into blackish grey on the 

 abdomen ; under wing-coverts white . . hybrida, p. 10. 

 b" . Bill black ; chin and sides of the face 

 black, like the underparts : under wing- 

 coverts pale grey. 

 a'". Underparts to vent dark lead-grey . . nigra, p. 17. 

 h'" . Underparts veiy deep black ; line along 

 the edge of carpals conspicuously 

 white mrinamensis, p. 20. 



b. White below (winter plumage and young). [p. 8. 



c . Tail white leucoptera ad. hiem., 



d'. Tail grey. 



c". Rump grey, like the back. 



c'". Larger : bill stouter ; feet with the 



webs much incised h/brida, p. 14. 



d'". Smaller : bill more slender ; feet with I nigra, p. 19. 



webs less incised ( s)irina7nensis, p. 20. 



d' . Ilump white, in contrast with the grey 



of the back and tail leucoptera ]\.\\ ., p. 8. 



