TROCHILIDJE — TROCHILINjE : HUMMING-BIRDS. 



459 



from the fact that, as in Passeres proper, the flexor lougus hallucis is independent of the flexor 

 longus digituruni, — that is, tlie muscle which bends the hind toe works separately from that 

 which Hexes the other toes collectively. The arrangement of the thigh muscles is the same as 

 in Ci/pselid(C. There is one carotid artery, the left ; a nude oil-gland ; no coeca. The pterylosis 

 is characteristic. 



The food of the Hammers was formerly supposed to be the sweets of flowers. It is now 

 known that they are chiefly insectivorous. Their little nests are models of architectural beauty. 

 The eggs are always two in number. The young hatch w^eak and helpless, requiring to be fed 

 by the parents, the Hummers being thus of altricial nature. The voice is not musical. 



The fiimily is one of the most perfectly cii-cumscribed in ornithology, and one of the largest 

 of its grade. So iuthnately and variously are the genera interrelated that every attempt to 

 divide it into subfamilies has proven unsatisftictory. The hummers are peculiar to America. 



Species occur from Alaska to Patagonia ; but we hav 

 centre of abundance is in 

 tropical South America, 

 particularly New Gra- 

 nada. Nearly 500 spe- 

 cies are current ; the 

 number of positively spe- 

 cific forms may be esti- 

 mated at about 400 or 

 more. The genera or 

 subgenera vary with au- 

 thors from 50 to 150. 

 The latest critical author- 

 ity upon the subject gives 

 426 species, assigned to 

 125 genera. (Elliot.) 



None of the known 

 N. A. Hummers exhibits 

 the extremes of shape of 

 bill or tail which some of 

 the tropical genera illus- 

 trate; in only one (Calo- 



n this country. The 



Fig. 299.- 

 (Sheppard del. 



Ruby-throated Humming-birds, cf , 

 Nichols sc.) 



? , and nest, nearly nat. size. 



thorax lucifer) is the bill decidedly curved. Only one species is as much as 4 inches long, — 

 the magnificent Eugenes fulgens. Some curious shapes of tail, including marked sexual 

 characters in this respect, are exhibited by certain genera. 



Only one species, the common Ruby-throat, is known to occur in the East ; this was the 

 only one known to Wilscm. Audubon gave four species, but one of them erroneously. Since 

 his time, however, new forms of these exquisite creatures have successively been brought to 

 light over our Mexican border. In 1858, Baird gave seven (one of them Lampornis mango, 

 erroneously, as Audubon had done). In 1872, in the " Key," 1 was able to increase the number 

 to ten, but with two wrongly given (the Lampornis and Agyrtria linna;i). The same ten, \vith 

 the two errors, were given by Baird and Ridgwayin 1874. Within a few years the discoveries 

 have been so many, that, after eliminating the two errors, I am able to describe no fewer than 

 fifteen perfectly distinct species of United States Humming-birds; and I have no doubt that 

 several others wall in due time be found over our Mexican border. 



The discrimination of the females and young is difficult ; but with the adult males there 

 should be no trouble. The following table is intended to enable the student to tell the genus 

 and species directly of any U. S. Hummer, if the specimen he has in hand be an adult male. 



