380 NOISES OF INSECTS. 



the various kinds of horse flies (Tabanus, Siomojc^s^ 

 Hippobosca) ; and of the Ethiopian zimb, as I have 

 before related at hirge"*, is the signal of intolerable 

 annoyance. Homer, in his Batrachomi/omacJiiay long 

 ago celebrated the first of these as a trumpeter — 



*' For their sonorous trumpets far renowird, 

 Of battle the dire charge mosqiiitos sound." 



Mr. Pope, in his translation, with his usual inaccuracy, 

 thinking- no doubt to improve upon his author, has 

 turned the old bard's gnats into hornets. In Guiana 

 these animals are distinguished by a name still more 

 tremendous, being called the devil's trumpeters''. I 

 have observed that early in the spring, before their 

 thirst for blood seizes them, gnats when flying emit no 

 sound. At tliis moment (Feb. 18th) two females are 

 flying about my windows in perfect silence. 



After this short account of insects that give notice 

 when they are upon the wing by the sounds that, pre-- 

 cede them, I must inquire by what means these sounds 

 are produced. Ordinarily, except perhaps in the case 

 of the gnat, they seem perfectly independent of the will 

 of the animal ; and in almost every instance, the sole 

 instruments that cause the noi^e of flying insects are 

 their wings, or some parts near to them, which, by their 

 friction against the trunk, occasion a vibration — as the 

 fingers upon the strings of a guitar — yielding a sound 

 more or less acute in proportion to the rapidity of their 

 flight — the action of the air perhaps upon these organs 

 giving it some modifications. Whetiier, in the beetles 

 that fly with noise, the elytra contribute more or less 



*- Vol. I. 2d Ed. 1 13. 146— " Sicdmau's Surinam, i. 24, 



