Birds of Celebes: Cypselidae. 
327 
speed, and dexterity in turning seem to be the only essentials. It may also 
be added that insects are much less sensitive to sound than birds and mammals, 
or have quite different perceptions of it. The cause may be quite different. 
The manifest influence of light, shelter, and exposure on the plumage -will be 
found referred to many times in earlier and later pages (Loricuhis^ Hierococcyx 
crassirostris, Graucalus, Coi-adas) ; the converse of sunlight (darkness) must of 
course also have effect, and in the soft glossless plumage of the Owls and Goat- 
suckers it may be that we see the influence of the want of light upon the 
feathers of birds. Night falls upon other birds also, but these are then sleeping 
and their vital energies are less active or otherwise employed. 
FAMILY CYPSELIDAE. 
The Swifts are diurnal birds of aerial habits, taking and devouring their 
insect-food on the wing. The bill is small, the nostrils membranous, the gape 
deep and wide, extending to below the eyes, the palate aegithognathous; the 
secondaries are much reduced, the primaries very long, 3 — 4 times the length 
of the secondaries or more; there are said to be no median wing-coverts; the 
legs are very short. The keel of the sternum is very high, the posterior margin 
unnotched. Three subfamilies have been distinguished — all occurring in the 
Celebesian Province; the Cypselinae with the three anterior toes consisting each 
of three phalanges, the tarsus feathered; the Chaeturinae with the tarsus bare 
and the toes normal, i. e. the middle one with 4, the outer with 5 phalanges ; 
the Macropteryginae with fenestra in the hinder margin of the sternum, and the 
tail extending about to the tips of the wings and deeply forked. 
GENUS CYPSELUS^) 111. 
The typical Swifts may be recognised by the toes which are naked and 
all directed forwards. Hartert (1892) recognised 16 species, of cosmopolitan 
distribution. Many of them migratory. They usually breed in holes in buildings 
or rocks, not forming a nest, laying white eggs. 
103. OYPSELUS PACIFICUS (LatE.). 
Australian Swift. 
a. Hirundo pacifica (1) Lath., Ind. Orn. Suppl. 1801, 58. 
b. Cypselus australis fl) Gld., P. Z. S. 1839, 141; (II) id., B. Austr. 1848, II, pi. 11; (III) 
Biggies, B. Axistr. 1877, p. 20, pi. 20. 
1) The genei'ic name ]}dlicropus of Meyer & Wolf (Taschenb. 1810, 280) antedates Cypselus of Illiger 
Prodr. 1811, 230) by a year. By rule 10 of the Stricklandian Code the name Micropus is to be rejected, 
