INSECTS INJURIOUS TO THE TURNIP CROPS. 31 
I suspect that the aphis was not primarily the cause of the 
injury to the Swedes, but that its attacks were induced by 
the previous unhealthiness of the plants, which had been 
caused by the maggots of the above-named fly already be- 
ginning their excavations. 
EXPLANATION OF PLATE. 
Fig. 1. Section of portion of turnip bulb affected by the larvae of Anthomyia 
brassicce. 
„ 2. The Earth-flea beetle ( Haltica nemorum) magnified. 
„ 3. Larva of Agrotis exclamationis — ( a ) nat. size ; (6) portion of ditto 
magnified. 
„ 4, 5. Imago of above — (4) male, (5) female. 
„ 6. Indurated skin of Aphis brassicce , showing at the posterior ex- 
tremity the opening through which the parasite Aphiclius rapce 
has emerged. 
„ 7. Larva of Anthomyia brassicce — (a) magnified, (b) nat. size. 
„ 8. Portion of anterior extremity of ditto, showing position of hook- 
shaped organ and lateral branchiae (magnified). 
„ 9. Side view of hooked organ (magnified). 
„ 10. Portion of anterior extremity, showing position of branchiae and 
their connection with the tracheal vessels (magnified). 
„ 11. Digitiform branchia, more highly magnified. 
„ 12. Pupa of Anthomyia — (6) nat. size, (a) magnified. 
„ 13. Perfect insect of Anthomyia radicum (magnified). 
All the above figures have been drawn for me by my kind friend R. S. 
Chattock, Esq., of Solihull, from specimens, with the exception of figures 
2 and 13, which have been copied from Curtis’s “ Farm Insects.” 
