INSECT ENEMIES. 325 



rove-beetles and the larvae of dipterous flies always 

 ready to seize upon disorganized vegetable tissue, and assist 

 its ultimate destruction. 



Even when the turnips are planted out for seed, their 

 dangers are not all over; as soon as they flower they 

 are liable to be infested by the "turnip-flower aphis" (A. 

 floris-rapce),&nd also to the visits of the "green rose-chafer" 

 (Cetonia aurata), which sometimes does great injury to 

 the flowers by destroying the anthers, and thus rendering 

 them abortive. This happens more frequently when 

 the seed is being grown in a garden than in the field, 

 especially if strawberry beds be near, in which this beetle 

 breeds. After the flowering is past, and the seed-pods 

 (siliques) formed, they are frequently found to be sadly 

 injured by the "turnip-seed weevil" (G. assimilis), which 



1 and 2. Weevil (natural size and magnified). 3 and 4. Maggot of Weevil 

 (natural size and magnified). 5. Exit hole in seed-pod. 6. Form in soil. 

 7 and 8. Pupae (natural size and magnified). 



inhabits the flowers, and bores a hole in the incipient 

 pods to lay its eggs in; the maggots then feed on the 

 seeds until they are ready to change their state, when 

 they eat their way out of the pod, and falling to the 

 ground, bury themselves, and pass in due time into the 

 state of pupse, from which the perfect insect, " the weevil," 

 emerges in the spring. 



The chemistry of the turnip has received the attention 

 its importance to our system of agriculture demands; and 



22 



