NOBLE: THE RESIDENT BIRDS OF GUADELOUPE. 371 
Lafresnaye (Rev. zool., 1844, p. 168) in his original description of 
Procellaria diabolica, referring to the larger specimens, says:— 
“Une espéce de Petrel, le Petrel Diable, du pére Labbat, Diablotin a 
la Guadeloupe, Procellaria diabolica L’Herminier, qui y arrive vers la 
fin de septembre, y niche en décembre dans les Falaises; une seconde 
espéce, en tout semblable de plumage 4 celle-ci, et n’en différant 
que par une taille moindre, y arrive 4 une autre époque, niche dans les 
mémes falaises, mais 4 un étage différent en hauteur, ce qui les fait 
distinguer 4 la Guadeloupe par les noms de Petrels des hauts et Petrels 
des bas. Ces deux oiseaux seront pris pour la méme espéce par tous 
les ornithologistes qui les posséderont sans renseignements sur leurs 
moeurs. Cependent M. L’Herminier les regarde comme constituant 
deux espéces bien distinctes, différant essentiellement de moeurs et 
d’epoque de passage. Mais n’anticipons pas sur les futurs documents 
que nous promet notre savant collégue, et qui auront un bien autre 
intérét sous sa plume et racontés de visu.” 
The two pairs of Black-capped Petrels from the Lafresnaye collec- 
tion are different from each other not only in size but in coloration 
and in shape of the nostril tubes. The smaller ones have the grey of 
the cap extending down the back of the neck and not terminating 
abruptly on the nape as in the larger birds, and the nostril tubes of 
the smaller birds are higher and end more abruptly than those of the 
larger specimens. In this respect as also in size the smaller birds are 
similar to Aestrelata jamaicensis. Each pair represents, I believe, a 
distinct species of Aestrelata. 
Which species, then, is Aestrelata haesitata? This is a difficult 
question to decide because of the uncertainty of the original descrip- 
tion. Kuhl (Beitrage zur zoologie, Frankfurt, A. M., 1820, p. 142) 
described a petrel “in Museo Bullokiano, nunc in Temminkiano” 
and calculated his measurements in terms of the “ pollex.”’ 
If we assume that the pollex was the Frankfurt a. M. inch of that 
time, as determined by the Bureau of Standards at Washington and 
sent me by letter, it is then possible that Kuhl’s specimen could be 
referable to either of the Guadeloupe species under consideration or 
better still to neither. Dr. Stejneger, however, recently told Mr. 
Bangs that Kuhl was a student of Temminck and would very likely 
have used the French system. Changing Kuhl’s measurements 
from French inches (Ridgway, Nomenclature of colors, 1886, pl. 17 
note) into millimeters and comparing them with the measurements 
of the Guadeloupe birds we find the figures more closely approximat- 
ing the measurements of the small than of the large species. But 
