122 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 " Pdchardsoni," 

 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 Brtinnich, 

 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 J. 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 " Richardsoni," 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 Briinn. ; Rkhardsoni Swains. . . ex 

 bor. Eur. et Am. Omni tempore et setate obscure unicolor." Swainson's figure 

 also represents the bird in this /wsco-j/ni'co/or 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. 



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