Observations on Insects affecting the Turnip Crops. 77 



of 16,000,000 of caterpillars, in the space of twelve months, viz. 

 from the spring of one year to the following spring. 



It is dispersed over all Europe, to the confines of Siberia and 

 China, and is also an inhabitant of North America. 



It flies by day as well as at night. 



Ducks, poultry, and sheep recommended to destroy the cater- 

 pillars. 



EXPLANATION OF THE PLATES. 



Fig. 1*. Aphis Rapee, male, a The natural dimensions. 



Fig. 2*. , female, h The natural size. 



Fig. 3*. , a young one just excluded. 



Fig. 4*. Aphis dubia. c The natural size. 



Fig. 5*. Aphis Brassicss, male, d The natural dimensions. 



Fig. 6*. , female, e The natural size. 



Fig. 7*. Aphis Floris-Rapse, male. /The natural dimensions. 



Fig. 8*. ■ , female, g The natural size. 



Fig. 9*. Front view of head of an Aphis magnified. 



h The rostrum or beak. 



i The compound eyes. 



k The three ocelli or simple eyes. 

 Fig. 10*. The head in profile of an Aphis magnified, showing the 

 rostrum and antennae. 



Fig. II*. One of the antennae or horns greatly magnified. 

 Fig. 12*. One of the six legs magnified. 



/ The thigh or femur. 



m The shank or tibia. 



n The foot or tarsus. 



The claws and pulvilli or suckers. 

 Fig. 13. The larva of a Coccinella or lady-bird. 



* The same magnified. . 

 Fig. 14. The pupa or chrysalis of ditto. 

 Fig. 15. The twin-spotted lady-bird. 

 Fig. 16. The seven-spotted ditto. 



Fig. 17*. The indurated skin of a female Aphis, from vdiich a para- 

 sitic fly has been hatched. 



p The natural size. 

 Fig. 18*. Aphidius Rapse, the parasitic fly alluded to, 



q The natural size. 

 Fig. 19. The larva of the golden-eye, called the Aphis-lion. 



* The same magnified, with the lichen removed. 

 Fig. 20.- The cocoon formed by the larva. 



Fig. 21. The golden-eye, Chrysopa perla, a female, at rest. 



Fig. 22. The eggs of ditto, copied from Reaumur, 



Fig. 23. The maggot or larva of Syrphus pijra-^tri, sucking an Aphis. 



Fig. 24. The pupa of ditto. 



Fig. 25. Syrplius pyrasiii, male. 



