STERILIZATION OF THE TETTIGID^. 165 



insect (if it follows the economy of Gonatopiis) does not, 

 to find its prey, quit its cyst; which is attached only to 

 its host by a narrow communication. 



It has been before noticed that the forms of certain 

 parts of the male genitalia furnish the most direct 

 diagnosis of the three small species of Typhlocyha, 

 recently added to our fauna. A question may arise, — 

 Do these parasites, by their action on the reproductive 

 organs, ever furnish a pseudo-species, that is to say, 

 simply a racial variety ? If a complete sterility in such 

 can be proved, we must conclude the above modifications 

 of genitalia to be monstrosities. If otherwise, care is 

 necessary that no parasitic interference has been at 

 work to complicate the morphological phenomena 

 before preparing the diagnoses of new species. 



The economist will take some interest in the above 

 remarks on sterility, for our corn crops are, as is well 

 known, often reduced in quantity through the destruc- 

 tion of the flowers of wheat and barley by a small red 

 Tipula or midge, Tipula tritici of Kirb. This gnat 

 devours the pollen, and of course this renders the ears 

 abortive. 



In conclusion I may be permitted to quote a note, 

 which is partly the translation of M. Giard's paper, 

 made by Mr. J. W. Douglas : — " Important modihca- 

 tions are seen in singular organs not hitherto noticed, 

 so far as I am aware, which exist in the males of 

 Typhlocyha Douglasi and T. liippocastani, the function 

 of which is quite enigmatical. They consist of two 

 invaginations of the integument that divides the 

 ventral surface of the segment of the abdomen, and 

 reach, like fingers of a glove, up to the extremity of 

 the fourth segment. These organs appeared to M. Giard 

 to be homologus with the phonetic apparatus of the 

 male Cicada. Under the name of Ateleneura spuria, pos- 

 sibly several different allied species are confounded."* 



* 1. Sur line galle produit chez le Tyjplilocyha rosce par uiie larva 

 d'Hymenoptere. ' Comptes Kendus,' p. 79. July, 1889. 2. Sur le castra- 

 tion parasitaire des Tyjphlocyha par Aphelo2nis et par Ateleneura. Also 

 p. 708. November, 1889. Par M. A. Giard. 



