Birds. 



8491 



thus imitating the action of the hummer as far as their very different 

 organization will permit. 



It is worthy of remark that the true allies of sun-birds in America, 

 the beautiful little Carebidae, which might naturally be expected to 

 show some sort of transition to the hummers if there were any real 

 connection between the groups, are still farther removed from them, 

 and have never been supposed by any observer or naturalist to have 

 the slightest af&nity with them, though obtaining much of their food 

 from flowers in a somewhat similar manner. 



The sun-birds, honeysuckers and allied groups are, I believe, related 

 intimately to the Epimachidae and paradise birds, with which they 

 agree in general internal structure, in the powerful and highly developed 

 grasping leg, in their activity and general high organization and special 

 adaptation to a purely arboreal existence ; and this affinity is most 

 beautifully shown in the little tufts of plumes from the breast and flanks 

 which appear in several distinct genera of these birds (Arachnothera, 

 Nectarinia, Moho, Prosthemadera and Ptilotis), and which form a 

 most constant and remarkable character in the Paridiseas. The won- 

 derful Neomorpha Gouldii (undoubtedly allied to this great group of 

 families), in which the bills of the two sexes differ so remarkably in 

 length and curvature that, judging from that organ alone, they might 

 be placed in distinct genera or even different families, tells us most 

 plainly that here the bill has become highly variable, and must be 

 expected to differ among birds otherwise intimately allied. A case 

 in point is that of the Paradiseidae and Epimachidae, families which 

 have been placed in distinct orders of birds owing to the difference of 

 their bills, but which, a knowledge of their internal and external struc- 

 ture, their food and habits, enables us to decide are most closely related, 

 so much so that they will probably have to form ultimately a single 

 family. 



In conclusion of this somewhat lengthy exposition I would express 

 my firm conviction, which I trust some of your readers will share with 

 me, that the sun-bird and the hummer have not a shadow of true 

 affinity, the former being a specialised form of an extensive group of 

 typical Passeres, the latter essentially a swift, profoundly modified for 

 an aerial and flower-frequenting existence, but still bearing in many 

 important peculiarities of structure the unmistakeable evidences of a 

 common ancestry. 



Alfred R. Wallace. 



