HUMMING-BIRDS. 



451 



ment precisely in the same manner ;is the honey-bee. In the spring months soon after 

 sunrise it sits on the top of a mango or orange tree, anil warbles a melody in a weak 

 but sweet tone, for minutes at a time. The nest is a cup, formed of silk cotton, orna- 

 mented outside with gray lichen. The movements of this bird's wings in flight are so 

 rapid that they produce a sound like an insect's hum. Thalurania contains eleven 

 species of moderate size and graceful forms, with a plumage of green or green and 

 blue, with metallic hues on the crown and throat, and sometimes on both. They have 

 a wide distribution from Central America to Peru. 



Fig. 221. — Topaxapella, topaz humming-bird. 



Aithxirus contains a very singular species from Jamaica, A. polytmus. It is one 

 of the longest known members of the family, and is conspicuous from the fact that the 

 Literal rectrices next to the outermost one on either side are nearly three times longer 

 than the otlier feathers, and are curved, and cross each other near their centre. The 

 head also has a somewhat lengthened black crest. It is very common in Jamaica, 

 ■where considerable numbers may be seen at one time performing their aerial evolu- 

 tions, chasing each other, or feeding from the various flowers. They do not always 

 probe these when on the wing, but may be seen thus engaged when sitting near them 

 on the brandi. The nest is composed of silk cotton, tlie outside quite covered with 

 spider's webs, and bits of lichens and bark stuck in here and there. The eggs are oval 



