' FURTHER EXPERIMENTS ON THE GENUS LASIUS. 137 



Exp. 9. September 19th, 1912. — I confined, as before, a naturally 

 dealated L. imibratii>; 2 in the outer chamber of the nest with ten ^ ^ . 

 She was not attacked at all durini^: the day. Next afternoon I removed 

 the barrier and she very soon entered the inner chamber, where she 

 was seized by three legs and an antenna. At the same time however 

 other ants saluted her. In the evening she was nearly dead, but no 

 longer attacked. Occasionally ants saluted and licked her. She was 

 in such a weak state that I did not think it possible for her to recover, 

 so I left her in the nest. Next morning she had recovered tea certain 

 extent and was able to walk about slowly, though one antenna was 

 badly twisted. No ants attacked her, and in fact she appeared 

 accepted. On the 22nd she had completely recovered, the only trace 

 of the rough treatment she had undergone being her bent antenna. 

 At the moment of writing (March 1918) she is in perfect condition 

 and surrounded by a court of ^ ^ . Thus it was only in a small 

 queenless colony that the parasitic ? was accepted, but in all the 

 nests, so long as the number of ^ ^ was small, the 2 was not 

 attacked. It is conceivable therefore that in nature a $ might enter 

 an outlying part of a nest, and be gradually accepted by most of 

 the S ^ until she was able to enter the nest proper. 



No cases are known of the host queen and the- parasite living to- 

 gether in a nest, so, unless a ? can only be adopted by a queenless 

 colony, it must sometimes happen that a J is accepted by a colony 

 already possessing a queen of its own species. In such a case the 

 intruder must either kill the rightful queen herself, as the queen of 

 BotJirioiinjmie.r kills the queen of her host, Tapinowa ■nv/erniiiuDi, or the 

 ^ ^ of the host species must themselves assassinate their own queen, 

 as do the ^ § of Tetra)iiorium cafspituw when they have accepted a $ 

 Anerr/ates atratidns. (Extr., 2nd Int. Cong. Ent. Oxford, 1912.) 



In order to throw some light, if possible, on this problem I confined 

 several queens of utiibratun with queens of ny/er. The results were 

 striking. 



Exp. 10. September 15th, 1912, 7.0 p.m. — A young fertile ? of 

 L. ttiiibnittffi and one of L. ny/er were isolated in a tin glass-top box. 

 They avoided each other as much as possible. At 11.0 p.m. the ni(jer 

 2 was dead. 



Exp. 11. September 16th, 1912, 1.0 p.m. — Another pair of young 

 fertile 2 2 were isolated. At 1.40 the nit/er 2 was nearly dead. 

 The Kinbratus 2 then came up, and, standing over the nii/er, bit 

 savagely at the pedicel. At 6.10 the nit/er was cut into three pieces. 



Exp. 12. — At the same time as the last experiment, another pair of 

 similar 2 2 was isolated. No attacking was observed during the day,, 

 but the following morning the ni/ier was dead. In this and the 

 previous experiment the ants were confined in glass tubes of half inch 

 bore, stopped by corks. The lunbratva 2 2 were able to gnaw away 

 the corks to a considerable extent, whereas the weaker mandibles of 

 the nvjer could make no impression on them. 



The supply of 2 2 having given out, I was unable to continue 

 these experiments. The last three, however, show that the L. 

 Kiiibratiis 2 ? will attack L. nifjer 2 2 and are able to kill them 

 easily, in spite of their smaller size, owing to the greater power of their 

 mandibles. A newly-fertilized 2 , then, fortunate enough to come 

 across an incipient colony of L. ni[ier, might easily disregard the 



