WHEELER. [VOL. II. 



fertilized by males from the same nest. There may be some 

 connection between this condition and the limited productivity 

 of these ants, and the strong tendency to parthenogenesis seen 

 in some of the species (e.g., in the ergatoid females of Pachy- 

 condyla liarpax}. 



The behavior of P. coarctata towards individuals of the same 

 species from different nests is very similar to that observed in 

 Pachycondyla. If two nests be thrown together into the same 

 dish, there may be no immediate signs of hostility ; but after a 

 few hours have elapsed, the ants are found struggling together 

 in pairs. They interlock mandibles or tug at each other's legs 

 and antennae, or even wrestle fiercely, intertwining their long 

 bodies and trying to use their slender stings. These contests 

 may be renewed from time to time for many days, whenever 

 two individuals from different nests happen to meet, but deaths 

 are rare, and ultimately the colonies fraternize completely. 

 Long before the ants have settled their various difficulties, 

 however, the cocoons and larvae of both nests are brought 

 together as common property. A dozen different nests can 

 be compounded quite as easily as two, and a few ants from one 

 nest can be induced to adopt a large number of cocoons and 

 larvae taken from half a dozen different nests. 



The eyes of the workers of P. coarctata are so very small 

 that they can hardly be of much service as visual organs. The 

 actions of the ants indicate that they are guided very largely 

 by their extremely sensitive antennae. They are, undoubtedly, 

 able to detect the difference between light and darkness, but 

 the fact that they do not seem to mind exposure to the light, 

 provided they are covered with a glass plate, leads me to infer 

 that they are rather positively stereotropic than negatively 

 heliotropic. Of course their preference for an atmosphere 

 charged with a certain amount of moisture --their positive 

 hygrotropism-- leads them to seek refuge in dark places, under 

 stones or the bark of old logs. 



I have not been able to ascertain the food of these ants in a 

 state of nature. They probably kill and imbibe the juices of 

 very small subterranean insects. In captivity they are omniv- 

 orous, feeding readily on raw or boiled meat, yolk of eggs, 



