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



that used both her mandibles and formic acid batteries. The second. female 

 was attacked jointly by two workers, but managed to escape to the light comer 

 of the nest, where she was found lurking at 2 p. m. By 4 p. m. she had been 

 discovered and killed. A very similar experiment with another small colony 

 of schanfussi gave the same result. 



Experiment 5. July 11, 11 a.m. A female consocians was placed in a 

 nest containing 12 workers and a queen of F. schaufiissi var. nitidiventris 

 together with several worker cocoons and larvas. The female consocians was 

 ignored by the female nitidiventris, but not by the workers, who kept dragging 

 her about by the legs and antennae. July 12 to 14 the female was being pulled 

 away from the nitidiventris queen and brood by the workers but kept return- 

 jng to them whenever she was released. At 1.40 p. m. on the latter date she 

 was found dead. Two more consocians females were at once placed in the nest. 

 Not only were these also attacked and pulled about by the workers, but they 

 began to attack each other although before deflation they had been living 

 amicably side by side in the parental nest. July 15, 7 a.m. One of the con- 

 socians was dead; the other kept lingering about the brood, apparently seeking 

 adoption. July 16 the same behavior was observed and was interrupted from 

 time to time by the workers pulling her away by the legs and antennae. On 

 July 17, 7.30 A.M., she was found dead in one comer of the nest. At 8.45 

 A.M. a fourth female was introduced. From time to time till 4 p.m. the usual 

 tugging and persistent returning of the female to the stack of cocoons were 

 observed. July 18, i p.m. the consocians female was resting peaceably beside 

 the nitidiventris queen on the pile of cocoons. No attacks on the former were 

 seen during the afternoon, but on the following day she was repeatedly pulled 

 away by the workers. July 20, 6.30 a.m. she was lying dead in a comer some 

 distance from the brood. At 8 a.m. a fifth female consocians was introduced. 

 At 6.30 P.M. she was resting with the brood and nitidiventris queen. Although 

 the colony was carefully watched on the following days, from July 21 to 26, 

 no attacks on this female were observed. She had been adopted without 

 remonstrance and behaved and was treated as if she had always been a mem- 

 ber of the colony. 



This experiment indicates that F. nitidiventris, though very closely 

 related to incerta, does not readily adopt consocians females, but that 

 this can be brought about by keeping the colony constantly supplied 

 with these females. In the experiment four were killed before one 

 was adopted. The perfectly indifferent attitude of the nitidiventris 

 female toward the intrusive consocians is very suggestive. It is pos- 

 sible that the presence of the mother of the workers may have de- 

 layed the adoption of a stranger. The var. nitidiventris seems to be 

 very rare in the Litchfield Hills. At any rate, I could not find another 

 colony on which to try the experiment without a nitidiventris queen. 



The results of experiments i to 5 seem to eliminate several species of 

 Formica from the list of possible hosts of F. consocians. It is so im- 

 probable that the other members of the genus occurring at Colebrook, 



