470 Mr. H. W. Bates on a Singing Cricket from the Amazons. 



a small wickcrwork cage, for the sake of hearing it sing. When 

 fed with pieces of cactus, the Tanana will live for two or three weeks 

 in captivity ; but its song, at first loud and sonorous, and audible at a 

 very long distance, becomes gradually feebler, and ceases altogether 

 before the end of that time. The individual from which the above 

 description is taken was kept by a friend of mine at Obydos in the way 

 here related. It used to chirp in the early hours of morning or late 

 in the evening. When producing the sound, the bladder-like elytra 

 were in a state of rapid vibration ; and the sound produced by the 

 swift passage of the file-like instrument of the one wing-case over 

 the horny edges of the other had a much more musical tone than I 

 have heard in any other Orthopterous insect. It was my impression 

 that the thin hard texture of the elytra and the hollow drum-like 

 space which they enclosed were the causes of the peculiar resonance 

 of its notes. The sounds produced had some resemblance to the 

 syllables Ta-na-na repeated in quick succession, and hence the 

 native name of the insect. 



Many excellent observations have been published on the stridula- 

 ting-organs of Orthopterous insects by Latreille, Goureau, and others ; 

 but the subject is well worthy of further investigation. The asym- 

 metrical form of the two halves of the organ, being portions of wing- 

 cases, which in all their conditions and variations are usually per- 

 fectly symmetrical in insects, strikes me as very curious. The en- 

 larged internal nervule which forms the file-like instrument of the left 

 elytron in Chlorocoslus Tanana exists on the right wing-case also, in 

 an enlarged condition, but perfectly smooth : it seems to perform no 

 function, but owes its enlargement to correlation. It is highly pro- 

 bable that the same nervule in the female of this insect would bo 

 (mite small and feeble, as it is in the females of other allied species, 

 whose males have beautifully elaborated singing- organs of a similar 

 nature to that of the Tanana. I was rather surprised to find the 

 wing-cases of the male house-cricket perfectly symmetrical. In this 

 species a different nervure to that employed in the Tanana is scored, 

 but the nervure is scored in the same way on both elytra. 



It is not until after much hesitation that I have decided to describe 

 the present insect as new to science. I am by no means sure that 

 it is not the Locusta camelli folia, described by Fabricius in ' Entom. 

 System.' torn. ii. p. 35. His phrase, " Elytra magna, concava, 

 viridia, nervosa, apice rotundata," seems to apply well to our species. 

 He does not, however, mention the remarkable vesicular appearance 

 of the insect. The expression " concava " is applied by him to the 

 elytra of many allied species of Locustariae. The Fabrician species 



