Standing in thick chestnut sprouts about as high as my head, where hundreds were around me, I observed the females coming around the drumming males." He adds, "this season (Aug. 1868) a dwarf pear-tree in my garden produced about fifty larvae of Cic. pruinosa; and I several times noticed the females to alight near a male while he was uttering his clanging notes." Fritz Muller writes to me from S. Brazil that he has often listened to a musical contest between two or three males of a species with a particularly loud voice, seated at a considerable distance from each other: as soon as one had finished his song, another immediately began, and then another. As there is so much rivalry between the males, it is probable that the females not only find them by their sounds, but that, like female birds, they are excited or allured by the male with the most attractive voice.
I have not heard of any well-marked cases of ornamental differences between the sexes of the Homoptera. Mr. Douglas informs me that there are three British species, in which the male is black or marked with black bands, whilst the females are pale-coloured or obscure.
ORDER, ORTHOPTERA (CRICKETS AND GRASSHOPPERS).
The males in the three saltatorial families in this Order are remarkable for their musical powers, namely the Achetidae or crickets, the Locustidae for which there is no equivalent English name, and the Acridiidae or grasshoppers. The stridulation produced by some of the Locustidae is so loud that it can be heard during the night at the distance of a mile (27. L. Guilding, 'Transactions of the Linnean Society,' vol. xv. p. 154.); and that made by certain species is not unmusical even to the human ear, so that the Indians on the Amazons keep them in wicker cages. All observers agree that the sounds serve either to call or excite the mute females. With respect to the migratory locusts of Russia, Korte has given (28. I state this on the authority of Koppen, 'Uber die Heuschrecken in Sudrussland,' 1866, p. 32, for I have in vain endeavoured to procure Korte's work.) an interesting case of selection by the female of a male. The males of this species (Pachytylus migratorius) whilst coupled with the female stridulate from anger or jealousy, if approached by other males. The house-cricket when surprised at night uses its voice to warn its fellows. (29. Gilbert White, 'Natural History of Selborne,' vol. ii. 1825, p. 262.) In North America the Katy-did (Platyphyllum concavum, one of the Locustidae) is described (30. Harris, 'Insects of New England,' 1842, p. 128.) as mounting on the upper branches of a tree, and in the evening beginning "his noisy babble, while rival notes issue from the neighbouring trees, and the groves resound with the call of Katy-did-she- did the live-long night." Mr. Bates, in speaking of the European field- cricket (one of the Achetidae), says "the male has been observed to place himself in the evening at the entrance of his burrow, and stridulate until a female approaches, when the louder notes are succeeded by a more subdued tone, whilst the successful musician caresses with his antennae the mate he has won." (31. 'The Naturalist on the Amazons,' vol. i. 1863, p. 252. Mr. Bates gives a very interesting discussion on the gradations in the musical apparatus of the three families. See also Westwood, 'Modern Classification of Insects,' vol. ii. pp. 445 and 453.) Dr. Scudder was able to excite one of these insects to answer him, by rubbing on a file with a quill. (32. 'Proceedings of the Boston Society of Natural History,' vol. xi. April 1868.) In both sexes a remarkable auditory apparatus has been discovered by Von Siebold, situated in the front legs. (33. 'Nouveau Manuel d'Anat. Comp.' (French translat.), tom. 1, 1850, p. 567.)
[Fig.11. Gryllus campestris (from Landois). Right-hand figure, under side of part of a wing-nervure, much magnified, showing the teeth, st. Left-hand figure, upper surface of wing-cover, with the projecting, smooth nervure, r, across which the teeth (st) are scraped.