LEPTOTHORAX. 153 



Birkenhead 25 , Morice found it in a nest of the same ant at Wood- 

 ham near By fleet, Hamm discovered a strong colony in a nest of 

 F. exsecta at Bovey Tracey 58 , Pool took males, winged females, 

 and workers in a rufa nest at Enfield 50 , and Hull sent me specimens 

 taken in March, 1912, in a nest of F. fusca at West Allendale 

 situated at a height of 1100 ft. 



Escherich states that L. acervorum occurs frequently in the 

 neighbourhood of nests of F. rufa and F. sanguined in Germany 51 . 



Wasmann records it from Holland under bark of fir and oak in 

 connection with Formica rufa, F. pratensis, F. sanguinea, and F. 

 fusca, under the bark of an old oak stump with a strong colony of 

 Donisthorpea fuliginosa, and in company with Myrmica ruginodis 

 under fir bark 23 . He found it at Lippspringe, Westphalia in July, 

 and in August, 1909, also with F. truncicola and M. laevinodis, but 

 very rarely with D. nigra (the Leptothorax being nearer the size of 

 the latter) ; on July 25th he discovered a small colony consisting of 

 males, winged females, and workers, under the bark of a mossy 

 stump in the middle of a nest of M . ruginodis ; and on August 26th 

 another colony of the Leptothorax, containing many queens, in a 

 nest of F. sanguinea in a root stump at Hoscheid. 



He considers that the " peaceable neighbourhood " with strange 

 ant species is the habitual and original condition of Leptothorax 51 . 



My own captures of this species in other ants' nests are as 

 follows : 



In the nest of F. rufa at Weybridge previous to 1902 42 occa- 

 sionally with F. sanguinea at Woking in 1906 50 males, winged 

 females, and workers in a nest of F. rufa at Nethy Bridge in July, 

 1908, and continually with F. rufa at Weybridge in 1910 58 a 

 worker in a nest of F. exsecta, and a deflated female in a nest of 

 F. pratensis at Rannoch on June 12th, 1911, and on a mountain 

 there on June 14th, 1911, two colonies under the same stones as 

 colonies of M . laevinodis ; both species had larvae and pupae, and 

 appeared to be quite friendly, they did not attack each other when 

 disturbed, and if they picked up each other's larvae, or pupae, 

 when taking them into safety, they put them down again 61 

 males, winged females, and workers under a stone of a F. rufa nest 

 in the New Forest on July 22nd, 1912 64 , and workers and larvae in 

 a nest of F. rufa at Weybridge on September 14th, 1912 65 a 

 deflated female, workers, larvae, and pupae in a nest of F. sanguinea 

 at Weybridge on July 12th, 1913, workers in two nests of F. rufa 

 v. alpina at Rannoch on July 16th, 1913, and a worker in a nest 

 of F. exsecta at Parkhurst Forest on August 23rd, 1913 68 . 



On July 12th, 1913, I introduced into my observation nest of 

 Formica sanguinea which is situated in a " Crawley-Lubbock " 

 nest a dealated female and a few workers of Leptothorax acer- 

 vorum taken in a sanguinea nest at Weybridge. The acervorum 

 were not attacked by the sanguinea and soon disappeared into the 



