256 INSECTS AND MAN 



habit of feeding the other workers who are on duty within 

 the nest, and one such worker was actually observed to feed 

 no less than fifteen of her companions, till, her supply 

 being exhausted, she went on her way, leaving some of 

 them hungry and still unsatisfied. 



The antagonism of the Argentine ant to all forms of 

 insect life, except scale insects and aphides, is remarkable; 

 as a rule, however, only those insects which are previously 

 injured fall an easy prey to these blood-thirsty insects. 

 Uninjured beetles, for example, are too fleet of foot and too 

 pachydermatous to be troubled, even by numbers of the 

 ants; but should misfortune overtake one of them, 

 thousands of individuals will overcome him and clean his 

 body piecemeal from his integument. Newly emerged 

 adult beetles also fall victims to these ants, for then their 

 bodies are soft and easily devoured ; in fact, the Argentine 

 ant is an adept at catching its prey in a helpless state, 

 either on account of injury or lack of development. Cock- 

 roaches are especially esteemed, but here, again, only the 

 injured are attacked ; at the same time, one of the few 

 natural enemies of this ant is the larva of a cockroach, 

 Thyrsocera cincta. 



The attention bestowed upon scale insects and aphides 

 by the Argentine ant has already been mentioned. Both 

 classes of insects are in the habit of inserting their beaks 

 or rostrums into plant tissues and withdrawing sap ; at the 

 same time, they exude a secretion which is usually sugary. 

 Newly hatched mealy-bugs individuals that have never 

 fed, and therefore never given off any secretion are totally 

 ignored by the ants, so it is evident that the secretion is 

 the attraction. Wherever the ants occur, these insect 

 pests have increased in numbers, and the reason is not far 

 to seek. The first, and most important, cause of increase 

 is the habit possessed by the ants of building shelters over 

 the insects; these so-called sheds are composed of fine 

 particles of earth, and they effectually protect the inmates 



