158 THE CAUSES WHICH PROPAGATE 



attenuated at either extremity, but more sharply so inwardly. 

 Superiorly it is flat, with indurated black pectinations of a fine- 

 ness that accords with the short aerial beats. During- confine- 

 ment we often notice the notes become more vehement in their 

 production, and this is a sure prelude to a mortal combat, and is 

 accompanied with the death of the musicians. 



The Meadow Cricket {Orcheliniiim vidgare), heard by Dr. 

 Scudder near Boston in America, commences with " ts,^^ which it 

 chang-es almost instantly into a trill of "zv"; at first there is a 

 crescendo movement which reaches its volume in half a second ; 

 the trill is then sustained for a period ^■arymg• from one to 

 twenty seconds, and closes suddenly with " p.''^ This strain is 

 followed by a series of staccato notes sounding- like "jip!"''; they 

 are one-eighth of a second in length, and are produced at one- 

 half second intervals. The staccato notes and the trill alternate 

 ad libitum. The night song differs from that of the day simply 

 in its slower movement ; the pitch of both is at B flat, two 

 octaves above the middle C. The kind is exotic. 



The genus Locusta of Burmeister, containing our familiar 

 Green Leaf-crickets, is not recognised as extending much 

 beyond Europe and the coasts of the central sea. The three or 

 more kinds likewise vary according to locality, and approach 

 each other very nearly in characters. One, Locusta cantanas, 

 has shorter and broader elytra, and is chiefly confined to the 

 mountain-ranges of Europe, where its notes, Yersin states, 

 change with the time of observation. When the sun hangs on 

 the horizon, its recitals are scarcely sustained during two or 

 three seconds with similar intervals ; later on they are pro- 

 longed. These hill-side sounds seem to come sharper and 

 briefer than those of the next species I shall notice, and more 

 run together, but its way of life is very similar. The commoner 

 kind, the Great Green Leaf-cricket, Locusta viridissima of 

 Linnaeus, mingles its dirl pleasantly with our recollections 

 of warm and dusty autumnal weather, and sweltering strolls and 

 seats beside fragrant brushwood, sun-tinged vineyards, and 

 cottage potherbs. In this country its chief resort is the potato 

 fields, to whose new-world foliage, like the Death^s Head Moth, 

 it has habituated itself, prompted by some unseen harmony, and 

 here over these noisome farm acres, during the months of July, 



