Voz. II, Pr. II] LOOMIS—A REVIEW OF THE TUBINARES 99 
hundred feet or more. One September day when a strong 
wind was blowing several were seen “sweeping along in great 
arcs, seldom flapping their wings.” In flying over the land to 
their breeding grounds, they flap their wings continually, but 
in returning to the water they change their mode of flight, two 
or three wing beats being followed by a long sail. 
The fact is worthy of record that a small centipede, belong- 
ing to a species inhabiting the humid belts of the Galapagos 
Islands, was found among the feathers of a Dark-rumped 
Petrel taken in latitude 3° 9’ S., longitude 91° 41’ W.* 
In the fresh plumage of both sexes, the feathers of the back 
and scapulars have a more or less grayish aspect, and are tipped 
in a varying degree with grayish white or light gray. Fading 
and wearing off of the tips of the feathers produce a uniform 
dark aspect quite different from the fresh plumage, at first 
glance suggesting a double form of coloration. The dark cap, 
so characteristic of some of the Pterodrome, is not wanting in 
the present species. It is especially conspicuous in birds in 
new attire. In certain specimens (notably No. 932 C. A. S.) 
the upper tail-coverts are tipped with grayish white. The 
greater and middle wing-coverts in some instances are more or 
less washed with ash-color and edged with grayish white (e. g. 
No. 970 C.A.S.). In a male (No. 947 C.A.S., June 18, 
1906) the dark color of the sides of the neck is extended 
across the jugulum in irregular transverse bars of gray, form- 
ing a band about an inch and a fourth in width. The sides are 
heavily barred with gray, becoming nearly uniform on the 
flanks; the back, too, appears to be exceptionally dark. 
The jugular and lateral markings occur in a lesser degree 
in numerous other Expedition specimens of both sexes, ob- 
tained at various times of the year. Whether dichromatism, 
age, or individual variation is illustrated in these peculiarities 
is not made clear in the Academy’s series. The under tail- 
coverts in some cases have indications of gray mottling. The 
white on the inner web of the primaries varies in extent; for 
example, on the first primary in No. 937 C.A.S., male, July 18, 
1906, it is concealed, while on the first primary in No. 1027 
C. A. S., male, June 11, 1906, it extends for an inch and three 
(ied Wore BE) Bn He eee DBT ae 
Biol. Surv., U. S. Dept. Agric., p. 11; Wallace, Island Life, p. 246, footnote; Hvatt 
and Pilsbry, Manual of Conchology, 2nd ser., pp. xiv, xv. 
