


RARER BIRDS OF MASSACHUSETTS. 643 
year Mr. Maynard succeeded in obtaining the young of S. 
macroura at Ipswich, when they were just able to leave 
the nest. A comparison of these with the young of S. 
hirundo of corresponding age, or even with mature 8. hi- 
rundo, leaves no question as to their distinctness. The dif- 
ferences between the young of the two are as great as 
between the adult. In these nestlings of S. macroura the 
color of the rump is as different from that of the back as it 
is in the adult, the plumbeous bluish mantle not being con- 
tinued to the tail as in S. Airundo. 
. The distinctive differences then between them may be 
stated thus : 
S. macroura has the under parts strongly tinged with 
plumbeous, with the throat and under tail coverts abruptly 
white, while in 8. hirundo the under parts are faintly washed | 
with plumbeous which fades gradually into white on the 
throat and under tail coverts. S. macroura has the shorter 
tarsi, and the shorter, smaller and more delicately shaped 
bill; in color the bill of the latter is uniformly carmine, not 
coral red with a black tip, as in the other, and the tarsi and 
feet deep vermilion, almost lake (not light vermilion as in 
S. hirundo), and roughened. The rump is abruptly white at 
all ages, while in I. Airundo it is dilute plumbeous, shading 
gradually into the color of the back. In size and general 
proportions there are no essential differences between them. 
So long as the young of jS. macroura was unknown, it 
seemed that the differences in color between the young of 
S. hirundo and the adult of that species, if carried a little 
further, would result in a form, so far as color is concerned, 
exactly like S. macroura.* 
RosEATE TERN. Sterna paradisea Brünn. Occurs plen- 
tifully on Muskeget Island during the breeding season. Was 
also taken by Mr. Maynard and myself at Ipswich in June, 
— 

*For an excellent revision of the Terns of North America, see Dr. Elliott Coues’ 
Paper on this subject in the Proceedings of the Philadelphia Academy of Natural Sci- 
ences, 1862, p. 535. 
