8 Bulletin American Museum of Natural History. [Vol. XXII, 



make the same appeal to the ants' sense of ownership as their own 

 larvae and pupae. This is certainly true of some other ants, like our 

 species of Lasius, which are very fond of cultivating white root 

 aphides and coccids in their subterranean galleries. Whenever the 

 stones covering their nests are overturned, the workers seize their 

 snowy charges in their mandibles and hurry away with them to a 

 place of safety. It is natural, therefore, that ants should try to 

 prevent the escape of their charges from a simple sense of proprietor- 

 ship such as all ants display towards their own brood. 



It is probable, moreover, that the protection of the aphides and 

 coccids from other insects is an instinctive precaution not so much 

 against the natural enemies of their charges, as against the larger 

 and more powerful ants, which are quite as fond of honey dew as C. 

 lineolata. This ant, being a weak and rather defenceless species, at 

 least while foraging at some distance from its nest, must often be 

 forced into competition with other aphidicolous and coccidicolous 

 ants like our larger species of Camponotus and Formica. The fact 

 that a herd of aphides or coccids is never attended by more than one 

 species of ant at a time ^ shows that the different species of ants are 

 quite as intolerant of one another on their feeding grounds as in their 

 nests. It is not improbable, therefore, that C. lineolata in construct- 

 ing tents over its charges merely emphasizes its sense of proprietor- 

 ship in the presence of the larger and more powerful ants with which 

 it has to compete in the struggle for existence; and it may well be 

 that the tents are constructed only in localities where such com- 

 petition-is unusually severe. 



That the tents may also serve to protect their occupants from the 

 cold seems not to have been suggested by previous authors. Brandes ^ 

 has shown that aphides — and the same is probably true of the 

 coccids — are relatively inactive before dawn and do not begin to 

 imbibe the juices of the plants till the diurnal temperature has risen 

 sufficiently. The tents, by protecting their occupants from the cold 

 night air, may thus prolong their feeding hours and increase the ex- 

 cretion of honey dew. This would, of course, be a decided advantage 

 to the ants. In support of this supposition we may note the singular 

 fact that the majority of authors above cited found the lineolata tents 

 late in the season (August and September) and in damp localities. 

 The cold, due to the greater evaporation in such places, coupled with 

 the lateness of the season, would probably tend to inhibit the feeding 



' Except in the case of Formica sanguinea and its slaves, F. fusca, and then only when the two 

 species belong to the same mixed colony. 



^ Die Blattlause und der Honigthau. Zeitschr. f. Naturwiss., 66 Bd. 1893, PP- 98-103. 



