348 MR. R. SW'INHOE ON THE BIRDS OF CHINA. [May 2, 



80. Ceryle lugubris, Temm. PI. Col. 548. 



A bird shot at Ningpo and described to me by a friend answers 

 to this species. 



81. Merops daudini, Cuv. ; G. R. Gray's Hand-list of Birds. 



Merops philippensis, Ibis, 1865, pp. 230, 348, 18/0, p. 91. 



Merops philippinus, Ibis, 18(56, p. 129. 



Procured at Swatow. For the edification of our Indian friends it 

 is well to state here that the so-called M. quint icolor from India is 

 not the same as the Javan bird. Tbe former differs from the latter 

 in having the under neck blotched with chestnut, and the tail green 

 instead of blue. Tbe Indian species should stand as M. erythro- 

 cephalus, Brisson, Av. iv. p. 563. 



82. Upupa epops, L. ; Zool. 1858, p. 6229 ; Ibis, 1860, p. 49, 

 1861, pp. 254, 328, 1867, p. 236 ; P. Z. S. 1863, p. 264. 



From Canton to Pekin. I described in the ' Zoologist' for 1858, 

 and in the P. Z. S. for 1863, the peculiar way in which the Hoopoe 

 produces its notes, by puffing out the sides of its neck and hammering 

 on the ground at the production of each note, thereby exhausting 

 the air at the end of the series of three which make up its song. 

 Before it repeats its call it repeats the puffing of the neck, with a 

 slight gurgling noise. When it is able to strike its bill the sound 

 is the correct " hoo-hoo-hoo ; " but when perched on a rope and only 

 jerking out the song with nods of the head, the notes more resemble 

 the syllables " hoh-hoh-hoh." Mr. Darwin makes use of this last 

 fact to show that some birds have instrumental means to produce 

 their music (Descent of Man, ii. p. 62). It is not to this point, 

 however, that I wish at present to call attention ; but to the fact of 

 the bird's puffing out the sides of its neck. It is generally supposed 

 that the song of a bird is produced by actions of the lower larynx on 

 air passing up the bronchial tubes, onwards and outwards through 

 the main tube or trachea. The trachea of the Hoopoe is not dila- 

 table ; but its oesophagus is ; and the puffing of its neck is caused by 

 the bulging of its oesophagus with swallowed air. There is no con- 

 nexion between the oesophagus and the trachea, and apparently no 

 organ at the entrance to the former that could modify sound ; what 

 action, then, can this swallowed air be made to take in the production 

 of the bird's notes? Pigeons have strikingly large air-crops, which 

 they empty with each long coo, and refill before they coo again. 

 Many birds swell out the throat when calling or singing, and others 

 move it up and down ; these actions must also be caused by the 

 swallowed air in the oesophagus, and must modify the sounds in some 

 way as variously used, adding power and richness in some cases, or 

 giving ventriloquistic effect in others. This question seems never to 

 have been inquired into before ; and I throw out the hint in hopes 

 that others may help to elucidate the matter with their investigations. 

 As regards Pigeons, Mr. W. B. Tegetmeier suggests "that the dila- 

 ted oesophngus and crop serve as a chamber of resonance, the air in 



