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PROCEEDINGS OF THE ACADEMY OF 
the appellation of parasitica ; for we take it, names and priority of discovery 
are not of the last importance ; all that is necessary is to be understood when 
we talk of species ; and for this purpose, a name sanctioned by usage, and 
which does not cause confusion, is far better than one which has nothing to 
recommend it but its priority of date.” 
It was by this somewhat heterodox reasoning on the subject of nomenclature, 
that Temminck adopted for the common Jager the name of “ Ric har dsoni,” 
and turned over the name “ parasitica” to the long-tailed species. His ex- 
ample has been very generally followed, as will be seen by consulting the 
synonyms given in this paper. I am inclined to the opinion, however, that 
Swainson’s bird may be a distinct species from the old parasitica of Briinnich, 
upon the following grounds : 
In the very extensive series of Jagers in the Museum of the Smithsonian 
Institution, there are several specimens which agree among themselves in the 
possession of some characters which differ considerably from those of the 
typical parasitica. The whole bird is considerably larger, — the difference in 
the wing from the flexure amounting to nearly or quite an inch, and propor- 
tionate discrepancies existing in the tarsi and toes. The bill is longer, (though 
not stouter ;) its nail longer compared with the ceral portion, and its convex- 
ity more gradual. The most marked features, however, lie in the tail. While 
the relative proportions of the lateral feathers to the central pair are much as 
in parasitica , the whole tail is longer, more graduated, and the individual 
feathers somewhat broader. From the insertion to the tips of the pair of 
feathers next the central, measures in parasitica about 5^ inches ; in “ Rich- 
ardsoni ” about 6 |. A proportionate difference exists in the absolute total 
length of the central pair; though their relative lengths do not differ appre- 
ciably. The tail of the specimens under consideration is more graduated, — 
the amount of graduation being nearly an inch, instead of about half an inch, 
as in parasitica. The central pair seem broader than in parasitica , and 
somewhat of a different shape ; and the same may be said, though less mark- 
edly, of the lateral feathers. Comparing some of these specimens which are 
in the dusky stage with the corresponding state of plumage of parasitica , I 
find the dusky to be much darker, — in fact, quite of a blackish rather than of 
a fuliginous hue. No other differences are appreciable. 
These specimens agree minutely with the plate and description of what 
Swainson called “ Ricliardsoni,” so that there cannot be the slightest doubt 
of the propriety of referring them to that species. The only question is, are 
the differences above detailed sufficient to constitute specific distinctions ? 
Bonaparte, in his Conspectus, ii. page 209, gives a form or variety of 
parasitica thus : “ a. L. coprotheres Brunn. ; Richardsoni Swains. . . ex 
bor. Eur. et Am. Omni tempore et setate obscure unicolor.” Swainson’s figure 
also represents the bird in this fusco-unicolor stage ; he perhaps thinking that 
this feature formed a distinctive character. This, however, cannot be the 
case ; and I wish to be distinctly understood as throwing this out of considera- 
tion altogether in discussing the claims of the bird to specific distinction, 
since it is now certain that this dusky stage is merely an evidence of immatur- 
ity ; and that the bird, when adult, will have the white neck all round, and 
white underparts, exactly as in parasitica. If it is to be separated at all, this 
is to be done upon the grounds of the differences in size and proportion above 
detailed, — without the least reference to the dusky stage of plumage in which 
it is figured by Swainson. 
While I am not thoroughly satisfied of the entire propriety of so doing, I 
shall, in the following Review of the subfamily, separate it specifically from 
the parasitica ; desiring to call attention to it, as at least a well-marked form, 
not a dist inct species. 
[May, 
