48 BULLETIN 647, U. S. DEPARTMENT OF AGRICULTURE. 



knocked from one part of the tree to another, often landing on the 

 trunk or larger branches. From 10 to 17 trees were examined each 

 time, and in all these inspections only 8 ants were found carrying 

 mealybugs, 7 of which were dead. In from one-half to 3 hours 

 after spraying an average of 3 mealybugs per tree were crawling up 

 the trunk; 18 hours after spraying the number had increased to 5 per 

 tree average; at about 48 hours after spraying there was on an 

 average only 1 mealybug returning to every 4 trees. Certainly the 

 ants did not assist to any appreciable extent in their return. 



The ants occasionally become impatient with aphids and scales 

 that fail to excrete and seize these insects, just as at times they be- 

 come impatient at waiting for an adult white fly to emerge f id 

 seize the pupa. The pile of mealybug remains found in the tree 

 nest previously referred to indicates that the mealybugs were utilized 

 as flesh food. There is little doubt that if sufficient time and pains 

 were taken the ants actually might be observed eating occasional 

 aphids and scale insects. 



RELATIONS WITH INSECT ENEMIES OF SCALES AND APHIDS. 



EXTENT OF CAPTURE OF PREDATORY AND PARASITIC INSECTS. 



The ants are antagonistic to all the predacious and parasitic 

 insect enemies of coccids and aphids, but not more so than they are 

 to all other insects which do not furnish them with honeydew. 

 The ants are habitually carnivorous and view all other insects, ex- 

 cepting perhaps some of the myrmecophiles, either as their cattle, 

 furnishing them with liquid food, or as their pre}^, useful as flesh 

 food. Although the ants take every opportunity to capture both 

 predators and parasites of the scales and plant-lice, the number of 

 this class of insects captured is very small. The close and constant 

 attendance of the ants at scales and aphids, by preventing free ovi- 

 position and feeding of the natural enemies, accounts mainly for the 

 ants 1 effectiveness as protectors of these pests, although the ants do 

 feed to some extent upon eggs of certain scale predators. 



A large number of insects have been taken from the ant and 

 identified, and only 0.72 per cent of all the insects carried have been 

 predatory on species attended by the ants. These consisted of larvae 

 of the Leucopidae, the brown lacewings, Syrphidae, and Lepidoptera, 

 the last very rarely, indeed. It is seen, therefore, that the number 

 of predatory enemies of the soft scales and aphids which the ant is 

 able to capture is insignificant. The number of internal parasites 

 captured is still smaller, being only one one-hundredth of 1 per 

 cent of the insects taken from the ants. 



