1915.] Chapman, New Colombian Birds. 661 
Molothrus bonariensis equatorialis subsp. nov. 
Char. subsp.— Size smaller than that of M. b. cabanisi, larger than that of M. b. 
bonariensis; the male resembling in color the males of other forms of this species; 
the female decidedly darker than the female of M. b. cassini and still darker than the 
female of M. b. occidentalis, much nearer the females of M. b. atronitens amd M. b. 
bonariensis, but much larger than the former, somewhat larger than the latter and 
with a larger, heavier bill. 
Type.— No. 118355, Am. Mus. Nat. Hist., 9 ad., Barbacoas, Narino, south- 
western Colombia; August 5, 1912; W. B. Richardson. 
Range.— Tropical Zone of the Pacific coast from extreme southwestern Colombia, 
south at least to the Province of Guayas, Ecuador. 
Remarks.— After discovering that the strongly marked form Molothrus 
bonariensis cabinisi (Cass.) occupies, with no apparent variation, the greater 
part of Colombia west of the Andes and even appears on the west slope of 
the Western Andes at Caldas, it was surprising to find that the Cowbird of 
southwestern Colombia and western Ecuador more nearly resembles M. 6. 
bonariensis, both in color and in size, than it does the race to which, geo- 
graphically, it is so much nearer. The absence of specimens from the 
Pacific coast (except from the Caldas pocket, which is believed to be an 
extension of the Cauca Valley fauna) north of the Patia, induces the belief 
that, as in some other cases, the relationships of the Ecuador and southwest 
Colombia race is actually with the upper Amazonian form rather than with 
that to the north of it. 
Molothrus bonariensis occidentalis (Berl. & Stolz.), of which I have a 
topotypical female, is evidently a pale form (paler even than cabanisz) from 
the arid Peruvian coast. A specimen from Daule near Guayaquil is the 
palest of my five females of equatorialis, and it may represent an actual 
approach toward occidentalis. A male in juvenal plumage from Puna Island 
is conspicuously paler than males in corresponding plumage from Barbacoas 
and Tumaco. Puna Island, however, is in the arid coastal zone and it is 
not improbable that specimens from this region should be referred to occt- 
dentalis. The remaining female specimens of e@quatorialis (Barbacoas, 1; 
Esmeraldas, 3) are all much darker, more blackish than any one of seven 
females of atronitens from Trinidad and the Paria Peninsula or of two 
females of M. b. bonariensis, one of which is from Conchitas near Buenos 
Aires, the type-locality of this race. 
Though closely approaching the latter form in size, equatorialis has a 
much heavier bill, and in this respect it resembles M. b. bonariensis. Meas- 
urements of the various forms are appended. 
