48 WHEELER. [VOL. II. 



P. coarctata is not found in deep woods or in damp places, 

 but prefers rather dry localities more or less open to the sun- 

 light. The margins of woods and along stone walls are favor- 

 ite haunts, under stones rather deeply imbedded in a rich soil, 

 especially leaf mold. Here it excavates a small, irregular cham- 

 ber, from which a few straggling burrows run off into the 

 neighboring soil. In some cases the chamber and burrows 

 are found under the lower surface of the stone, but I have 

 gained the impression, from the examination of many nests, 

 that the ants often prefer the vegetable mold nearer the sur- 

 face, where it overlaps the sides of the stones. Chambers and 

 galleries of the same irregular pattern are excavated in the 

 rotten wood when the ants nest under the bark of old logs. 

 The larvae and pupae are reared in the chambers. In late 

 June and early July the nests contain eggs and larvae but no 

 pupae; during the latter half of July and the month of August 

 only cocoons are found, usually crowding the chamber so that 

 the ants have little space in which to move over and among 

 them. The imagines begin to hatch during the last two weeks 

 of August and the first week of September. Even by the 

 latter date I have seen no eggs nor larvae to represent a 

 second brood. 



The number of individuals composing a colony varies in dif- 

 ferent nests and with the advance of the summer. As the 

 ants are very timid and at once seek refuge in their galleries 

 as soon as the stone that covers the nest is moved, it is not 

 easy to determine their precise numbers. None of the nests 

 opened at Rockford, 111., July i, contained more than eight or 

 ten ants, including a single female. As soon as the cocoons 

 begin to hatch, the colony increases rapidly. One rather 

 typical nest, opened at Colebrook, Conn., August 24, con- 

 tained six males, one female (with wing stumps and evidently 

 the mother of the colony), one callow virgin female, twelve 



subsp. pennsylvanica Buckl. ; Myrmicuia Latreillei Curt., subsp. americana Em. ; 

 Formicoxenus nitidulus Nyl.; Solenopsis molesta Say; Crematogaster lineolata Say, 

 var. ; Stcimmma (Aphaenogastcr'} fnlvum Rog., subsp. aquia Buckl., var. piccnnt 

 Km.; Myrmica rubra L., subsp. scabrinodis Nyl., var. Schencki Em.; Tapinoma 

 sessile Say. 



