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the night ; Fore], that they may seek their food by night as well 

 as by day, but do not then occupy themselves in building, and 

 remarks that their activity in general depends upon tempera- 

 ture, and they are often quiet at night simply because it is too 

 cool for them to work. McCook's observations point to the 

 same conclusion, but he found the ants both feeding and build- 

 ing at night, their activity in building clearly depending upon 

 the moisture of the ground ; when the nights were cold he 

 found the ants torpid on the trees, beside their aphid flocks, 

 just as the cold had surprised them. Here they would resume 

 their activities with returning warmth. Observations in mid- 

 winter shoAv that the colonies then remain still active in the 

 galleries directly beneath their mounds ; at the same time the 

 interstices of the mounds may be occupied by the hardier white- 

 ants and by cockroaches. No colonies of Aphides nor any 

 source of food were found within reach ; but in this connection 

 it may be mentioned that Dr. Leidy has this year found in a 

 single formicary of Lasius flavus two large herds of Aphides and 

 one of Coccidae, sufficient, no doubt, to feed the colony for an 

 entire winter. 



The paths diverging from the ant-hills invariably lead to 

 plants or trees occupied by colonies of Aphides. These are 

 visited by immense numbers of ants, who gorge themselves 

 with honey-dew and return to feed the occupants of the nest. 

 Mr. McCook was astonished, however, to see how few of these 

 " repletes," as he calls them, actually returned to the nest ; 

 and thus was led to the discovery that many of them were 

 stopped on their return, by hungry workers, "pensioners" he 

 calls them, emerging from the openings of the subterranean 

 galleries, and were compelled to disgorge, so that the queens, 

 males and young ants at home must have fared ill. 



Mr. McCook has made the interesting discovery of another 

 source of honey-dew for ants. At former meetings I have called 

 your attention to the description given twelve years ago, by 

 Guen(5e, of peculiar organs on some of the hinder segments of 

 Lycffinid larva?, which may emit a drop of fluid. This is the 

 new pasture which Mr. McCook has independently discovered 

 by seeing the ants stroke the larvae with their antennas, in the 



