ENSANAFU AND STINK ANTS 281 



was a small, thin bodied, long legged insect whose appear- 

 ance suggested a Syrphid fly, though one seemed to have 

 a short ovipositor, which would imply that it was an 

 " Ichneumon " fly. 



After watching for some time I suspected that the 

 fly's object was to dart down and lay an egg upon a 

 cockroach before it was cut up by the ants. Presumably 

 the egg would thus be carried into the nest, where the 

 larva would find food that it required, and possibly frag- 

 ments of insects that had been brought in by the ants. 



Bates, in his Naturalist on the Amazons, describes 

 something similar in the case of Stylogaster and the Eciton 

 ant, which has habits analogous to those of Dorylus. 



In July 1914, I saw an interesting affair on Bulago 

 Island. A small column of Ensanafu was hunting, and 

 had discovered in a hollow, broken cane stem the nest of 

 another ant, a large black species whose rotund abdomen 

 is covered with golden pubescence. The rightful owners 

 of the nest had found discretion the better part of valour, 

 and were no longer attempting to resist the raiders, who 

 had bitten through the stopper closing one end of the 

 stem. Some, inside, brought up the grubs in the nest, 

 which were at once seized by eager helpers outside, who 

 usually fell to the ground with their burden in their 

 excitement. It was a busy scene, and curiously reminded 

 one of the unloading of a ship. 



Another abundant ant is the giant Paltothyreus tarsatus, 

 known to natives as " Waka," and to Europeans as 

 " Stink ant," owing to the appalling smell of bad eggs 

 emitted by it when roughly handled. About an inch 

 long, coal black in colour, this species is often seen singly 

 slowly wandering about searching for food. It seems to 

 live on animal food — small insects or bits of dead ones 

 which it meets with on its wanderings — but is not active 

 in its movements. If handled it can inflict a severe sting. 



The Waka nests underground, and in disused chambers 



