160 TRUCK-FARMING AT THE SOUTH. 



Besides these, there are many less common kinds. 



Prominent among the enemies of the plant-lice are 

 the larvae of the Golden-eyed and Lace- winged flies, 

 called Aphis-lions. 



Other enemies are the larvae of Syrphus-flies, somewhat 

 resembling a leech in shape. Besides being preyed upon 

 by all these insects, the plant-lice are subject to several 

 genera of tiny parasites included in the genus ApMdius. 



Fig. 31. HARLEQUIN CABBAGE BUG (StracUa histrionica). 

 a, Larva ; ft, Pupa ; c, Eggs ; d, Perfect Bug. 



They have mostly black bodies, and are about one-twen- 

 tieth of an inch in length. The little round, plump, 

 smooth bodies in a colony of aphides, or remaining on 

 the leaf of a plant after the removal of the colony by 

 other enemies, are dead parasitized aphides containing the 

 parasitic pupa of an ichneumon fly. 



The Harlequin-bug made its appearance in Georgia, 

 from Mexico, about the commencement of Mr. Lincoln's 

 first presidency, from which circumstances it received the 

 local name of " Lincoln-bug," by which it is still known 

 in Southern Georgia. In 1867 it had reached North 

 Carolina. 



This insect winters in its perfect state, and the first 



