.9^. THE DEVELOPMENT OF INSECTS. 283 



d'Herculais and C. Langlois (6). This fly was described by Haliday 

 in 1836 from a single specimen captured in the north of Ireland. 

 Since then only four more examples had been taken, one in Germany 

 and three in England ; but now the insect has been found in myriads 

 in Algeria, attacking with great effect the larval and perfect stages of 

 a beetle [Haltica ampelophaga, Guer.) which is extremely destructive 

 to vines. 



The parasitic grub of the ichneumon feeds singly within the 

 larva of the beetle, avoiding the vital parts but devouring the fat- 

 body, and thus rendering further development impossible. Fifty to 

 eighty out of every hundred beetle-larvae examined were affected, 

 and the adult beetles are also liable to be attacked. The value of 

 this parasite to owners of vineyards is evident, and we have another 

 instance of man's best allies against the insect-destroyers of his crops 

 being themselves insects. The study of the development of insects 

 not only enables us to speculate on the nature of their far-distant 

 ancestors, but teaches us how in some measure to save from 

 destruction " the kindly fruits of the earth." 



REFERENCES. 



1. Chapman, T. A. — Some Facts towards a Life-history of i?/u^;^Ao>'Mj/a>'aio;tr«s. 



Ann. Mag. Nat. Hist., ser. 4, vol. vi., p. 314, 1870. 



2. Chobaut, A. — Moeurs at Metamorphoses de Emtnadia flabellata. Ann. Soc. 



Entom., France, 1891, p. 447. 



3. Cholodkowsky, N. — Die Embryonalentwicklung von Phyllodromia germanica. 



Mem. Acad. Imp. Set. St. Petirslourg, ser. 7, vol. xxxviii., No. 5, 1891. 



4. Sedgwick, A. — The Development of the Cape Species of Peripatus. Quart. 



Journ. Micro. Sci., vol. xxv., p. 449; vol xxvi., p. 175, 1885-86. 



5. Kulagin, N.— Zur Entwicklungsgeschichte der parasitischen Hautfliigler. 



Zool. Anxeiger, vol. xv., p. 85, 1892. 



6. Kiinckel d'Herculais, J., and Langlois, C— Moeurs et Metamorphoses 



de Perilitus brevicoUis. Ann. Soc. Entom., France, 1S91, p. 457. 



Geo. H. Carpenter. 



