ON THE COLOURS OF THE FEATHERS OF BIRDS. 299 



distance upon a leaf, with the antennae hanging down as if they were 

 asleep, on which account I directed a pocket-telescope to the spot, 

 which was above five feet distant, and therefore convenient for viewing 

 the insect. The point of view being thus determined, I made a loud 

 sound, and I was delighted with the opportunity of seeing the weevil 

 not only roused, but the antennae which had been hanging down 

 became elongated, and being full of joints struck by the undulations 

 of sound they extended themselves and remained on the alert till 

 alarmed again by a fresh sound. The insects fell down on the ground, 

 as is the habit of those and other weevils. I have never attended to 

 any proof of hearing in spiders, among which the want of antennae is 

 supplied by acute sight and smell ; but all these proofs weighed toge- 

 ther and separately, seem to add strength to the probability of our con- 

 jecture, namely, that the antennae are given to insects for the purpose 

 of perceiving and recognising sounds, in a similar manner as the sails 

 of a ship serve to convert the wind to the use of the sailor ; from which 

 analogy and comparison, I suppose that this name has been assigned 

 to these organs of insects. 



ON THE COLOURS OF THE FEATHERS OF BIRDS. 



BY L. P. VIEILLOT, MEMBER OF THE INSTITUTE, PARIS*. 



THE American Indians give the humming birds a name which 

 signifies sun-beam, expressive of their splendour and rapidity of 

 motion, in some species producing an effect similar to that of the fires 

 which flash through the upper air in the fine nights of summer, popu- 

 larly termed falling stars. Upon the arrival of the Spaniards in Peru, 

 the conquerors beheld with admiration the pictures composed by the 

 Indians with the feathers of the colibris. All travellers agree in ac- 

 knowledging the beauty and delicacy of these pictures; and in fact, it 

 requires no great stretch of imagination to fancy their brilliancy and 

 freshness. 



The plumage of the humming birds, sparkles not only with the 

 liveliest colours, but these colours possess ^he property of varying their 

 shades according to the direction in which the light falls upon them. 



* Translated from the splendid French work " Oiseaux Dores " by Miss 

 H. G , Lee, Kent. 



