173 THE CAUSES WHICH PROPAGATE 



summer-time are all resounding- with these populous cries ; 

 and here I had inserted the ordinary challeng-e in my pocket- 

 book as '^ wrree." Yersin also similarly notates it " vrrriiii/' 

 and he says it lasts rarely more than seven or eig-ht seconds^ and 

 consists of from one to three notes ; but on ag-ain hearing the 

 same music trilling fifteen to twenty seconds in the hay-fields of 

 Piedmont, I sat down, and after some cogitation, decided on the 

 present enunciation as more expressive. The various sounds are all 

 due to the vibration produced by about seventy tubercular teeth, 

 very uniform as to size and distance of insertion along the ridge 

 of either hind femur, and their distinction and modulation is due 

 to the play of the hind legs. 



The Stenobothriis vagans inhabits Central Europe. Yersin 

 says it is abundant in the Valais from Fouly to Sion, where it 

 may be commonly heard on the stones at the wayside. It emits 

 four notes a second, which are clear and more or less separated, 

 '' eee,^^ or " rrreeee,^'' and this music lasts from two to five 

 seconds. Dry stony margins of hilly fields are the common 

 resort of the species, which resembles greatly the Variable 

 Grasshopper, save in its being less downy, and having the 

 lateral keels on the thorax less cross-shaped. Another grass- 

 hopper with more northern distribution, the Stenolothrus 

 apricarius, is heard on the Alps from August to October. It 

 seems an unusually powerful minstrel, since it emits ninety notes 

 in fourteen or fifteen seconds, which gradually augment in 

 fulness, " E-tin ! e-tin ! e-tin ! " the two sounds appearing to 

 arise from the backward and forward movements of the femora 

 being made with different pressure. It frequents similar spots 

 to the former. 



The male of StenobotJirus melanopterus, with transparent 

 wings strongly bowed outward in front, and dirty umber veins, 

 does not appear recorded as being found in this country, 

 although it is by no means unfrequent on the opposite French 

 coast, and is distributed over the greater part of Europe. Its 

 powerful notes with a timbre " ssssin,^' we glean from Yersin's 

 papers in the bulletins of the Vaudoise Society, are followed by 

 another graver, resulting from a simple elongate stroke of the 

 legs which press on the elytra during their upward movement, 

 " trrrraa,^^ or the two notes combined^ '^ ssssin, trrrraa.'^ Some- 



