HIRUNDO ATROC@RULEA, 367 
by the original projectors, and the parent birds safely brought up 
their young. The nest of this Swallow is cup-shaped, and the eggs 
pure white.” 
This little Swallow may be told by its entirely blue head and 
wholly white undersurface. 
Adult.—Above purplish blue: quills brownish black, grey on the 
inner web, the innermost of the greater wing-coverts white, forming 
a white spot, which, however, is generally concealed by the scapu- 
lars ; occasionally in very old birds a small white spot also occurs on 
the innermost secondaries: tail brownish black, without any spots, 
glossed on the upper surface with dark blue, with a faint greenish 
lustre; entire under surface silky white, having in some specimens 
a certain woolly appearance, greyish in certain lights: on each side 
of the upper breast a patch of dark blue feathers: “bill and feet 
black: iris dark brown.” (Andersson). Total length, 5°5 inches ; 
wing, 4°2; tail, 2°6; tarsus, 0°4. 
Young.—Not so bright above, and more distinctly tinged with 
greenish: the white spot on the greater wing-coverts either absent 
altogether, or when present, of a dull greyish colour, and very little 
developed. ; 
Fig. Cass. Pr. Philad. Acad. V., pl. 12. 
351.—HiIRuNDO ATROCE@RULEA. Blue Swallow. 
(Plate IX. fig. 1). 
This very distinct species of Swallow is distinguished by its 
entirely blue colour above and below. It is a native of Natal, where 
it was first discovered by the late Professor Wahlberg. Mr. Thomas 
Ayres writes from the same colony :—“ These are the most uncommon 
of the Swallows here ; they frequent the open country, and appear 
to be solitary in their habits, skimming with rapidity and ease over 
the long grassy hills. Ihave never seen them take a rest, but on 
and on they go, apparently without ceasing. They are, I think, 
here all the year round; at all events, I have seen them in the 
following months, viz. March, April, August, November, and 
December.” 
Adult.—Entirely glossy blue-black, a little more dusky underneath : 
shafts of the primaries and of the tail-feathers white and very plain 
on the underside: bill black: feet dark brown. Total length, 7:2 
inches ; culmen, 0°3; wing, 4°5; tail, 4°6; tarsus, 0°35, 
