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COCCYGUS ERYTHROPTHALMUS. 
The bill is curved while the gape is wide and deep. The stomach is not muscular and 
there are moderately long coeca. The tail is quite long but not greatly exceeding the wings 
in length. The tail is considerably graduated. 
GENUS I. COCCYGUS. THE AMERICAN CUCKOOS. 
Gen. Cii. General colors are brown above and white below. No bands or conspicuous spots anywhere on the body. 
Tail , more or less broadly tipped with white. 
The sternum is as given under Family characters, as is also the bill. The larynx is provided with a rather stout sterno- 
trachealis and a broncho-trachealis posticus both of which have their tracheal origin at the same height; the lower ex¬ 
tremity of the latter is attached to the bony half rings of the larynx. The tympaniform membrane is present and the os 
transversal© supports a slight semilunar membrane. The oesophagus is without dilatation and opens into a large, rather 
globular, proventriculus which has quite thick walls composed of long oval glands which are arranged in a zonular band 
and measure in erylhropthalmus -10 in length. The stomach is a rather spherical sack with very thin walls and is lined 
with a soft membrane which is, at least in our two northern species, covered with hairs that, under the microscope, resem¬ 
ble those from caterpillars. The duodenum is very short and incloses a compact pancreas which, although short, is quite 
wide at the upper extremity. The coeca are long with the blind ends somewhat dilated. The spleen is an oval body situa¬ 
ted nearly over the cardiac opening of the stomach and is quite granular in structure. The tibse are covered with long 
feathers but the tarsi are only slightly feathered on the extreme upper anterior surface. 
COCCYGUS ERYTHROPTHALMUS. 
Blaek-billed. Cuckoo.' 
Coccygus erylhropthalmus Bon., Obs. Wils.; 1835, 48. 
DESCRIPTION. 
Sp. Cii. Form, not very robust. Size, medium. Sternum, not very stout. Tongue, long, thin, wide at the base, and 
quite horny, especially near the tip which is bifid, and about one third of the terminal portion of the sides is provided with 
coarse cilia. Space around eye, naked. 
Color. Adult. Above, including wings and tail, reddish-brown with a decidedly greenish gloss everywhere except¬ 
ing on top of the head where there is an under tint of plumbeous. Beneath, white, with the throat, upper breast, abdomen, 
and under wing and tail coverts, overwashed with yellowish-rufous. Two thirds of the basal portion of the inner webs of 
the wing feathers are also yellowish-rufous. Central pair of tail feathers slightly, and all the others more broadly, tipped 
with white which on all, but the two former, Is preceded by a band of dusky. Sides of head, plumbeous. Naked space a- 
round eye, including eyelid, scarlet. Bill, black, blue on basal two thirds of lower mandible. Feet, bluish. 
Young. Very similar to the above but the tail is only slightly tipped with white and the dusky subterminal band is 
not as clear. There is less yellowish-rufous below, while the lower mandible is not as blue. 
Nestlings. Are not unlike the above, but their appearance is changed considerably by the feathers of the upper parts 
being narrowly edged with white. The colors are purer, there being only a trace of the yellowish overwashing, but ail 
the feathers show dusky centers. Bill, as in the young stage of plumage but the feet are brown. Sexes, similar in all 
stages. 
OBSERVATIONS. 
Specimens vary greatly in size but, although some are much larger than others, yet the increase is well proportioned. 
The nestlings are able to fly some time before they assume the full length of tail or attain the size of the adult. One now 
before me and which had left the nest, presents a singular feature for it yet retains the egg tooth on the tip of the upper 
mandible that almost all birds lose in a few days after birth. Readily known from the two remaining species of this genus 
which occur within our limits by the narrow white tipping to the tail and also by the bluish tint on the under mandible. 
Distributed during summer throughout Eastern United States from the latitude of Georgia to that of the White Mountains. 
Winters in South America. 
DIMENSIONS. 
Average measurements of thirteen specimens from New England. Length, ll*85j stretch, 10*25; wing, 5*70; tail, 5 - 55; 
bill, *90; tarsus, '92. Longest specimen, 12'70; greatest extentof wing, WOO; longest wing, 6'00; tail, 6 - 61; bill, - 95; tar¬ 
sus, l’OO. Shortest specimen, ll'OO; smallest extent of wing, 15*50; shortest wing, 5 - 40; tail, 4 - 50; bill, '85; tarsus, '85. 
