Diomedella cauta. 
WHITE-CAPPED MOLLYMAWK. 
From the American Museum Novitates, No. 419, April 5th, 1930, I take the 
following from Dr. R. C. Murphy’s account, and Falla, Rec. Auck. Mus., Vol. I., 
p. 179, 1933. 
D. c. cauta. Head and nape w r hite, with a grey tinge on the cheeks. 
Average measurements : wing 564*8, tail 203*6, culmen 134T, width of maxilla 
at base 32*5 ; depth of closed bill at base 54*7, tarsus 92*4, middle toe with 
claw, 137*2 mm. Bill grey, with the tip of the maxilla horn-colour; feet and 
legs grey. 
D. c. salvini. Head and nape light grey, the peleum distinctly paler. 
Average measurements : wing 556, tail 205, culmen 128, width of maxilla at 
base 30; depth of closed bill at base 51*6, tarsus 88*1, middle toe with claw 
131‘3 mm. Bill bluish or greenish-grey, with a homy or ivory culmen, and a 
blackish terminal spot on the mandible. The transverse fleshy stripe at the 
base of the mandible orange. Legs and feet bluish (grey). 
D. c. eremita. Head and nape dark grey; peleum little, if any, lighter. 
Average measurements : wing 546, tail 209, culmen 125*7 ; width of maxilla 
at base 30*1 ; depth of closed bill at base 51*4 ; tarsus 86*2 ; middle toe with 
claw 128 mm. Bill entirely bright yellow. Entire culmen light cadmium ; 
latericom deep chrome, slightly lighter basally; mandible deep chrome, with 
the ramus lighter and the distal plate terminating in a dusky spot; transverse 
line at the base of the mandible orange, which colour is continued along the 
gape of the mouth ; narrow" skin between the plates of the bill and feathering, 
and also that extending to the nostrils between the culminicorn and the 
latericorn, black; feet whitish or bluish-white. 
D. c. steadi. Head and neck white, with a tinge of grey on the cheeks ; 
white throat and neck, and white on the inner w r eb of the primaries. Measure¬ 
ments : wing 610, tail 252, culmen 140, tarsus 90, middle toe and claw 142. 
Bill cream-yellow, feet bluish-white. Breeding on the islands south of Stewart 
Island, New Zealand. 
So we have : — 
wing. 
tail. 
culmen. 
tarsus. 
cauta 
564*8 
203*6 
134*1 
92*4 
salvini 
556 
205*0 
128*0 
88*1 
eremita 
546 
209*0 
125*7 
86*2 
steadi 
610 
252*0 
140*0 
90 
An average of from 8 mm. to 10 between the sub-species in wing measure¬ 
ments ; 1*4 to 4 in the tail; 2*3 to 6*1 in the culmen ; 1*9 to 4*3 in the tarsus 
excluding steadi. 
The young moult from the light neutral-grey down into adult coloration. 
Bill blackish, which turns to grey as the birds get older. Feet light bluish, 
almost white sometimes. 
59 
