272 BRITISH ANTS. 



points out, this is not the usual practice, and ants which are unwell, 

 are more often deserted, or thrown out of the nest, which has 

 generally been my own experience. Forel has observed workers of 

 pratensis playing together, performing gymnastics, etc., such as 

 we have already seen to be performed by those of rufa. 



The food of pratensis is similar to that of rufa, and Miiller records 

 finding workers of the former on flowers of Rosaceae and Com- 

 positae 21 . 



There is no fixed time for the appearance of the winged forms, 

 nor for the marriage flight of F. pratensis, indeed Forel states with 

 regard to the swarming, that this is the most irregular of all ants 

 in that respect. He has found the males and winged females in the 

 nests in Switzerland in May, June, July, August, and September, 

 the earliest date being May 2nd 26 . 



Forster records the winged sexes at Aachen at the beginning of 

 May, appearing most commonly in the early morning 8 . 



Schenck found males in a colony at Weilburg on May 16th, 1882, 

 this sex not having occurred until June 1st, in the same nest the 

 year before 11 . He says they come up on to the top of the nest at 

 from seven to nine, or ten o'clock in the morning, but do not appear 

 later in the day 10 , and he has noticed that as soon as they show 

 signs of leaving the nest, the workers take them back by force, even 

 dragging them from the grass stems near by, into the nest 9 . He 

 observed a double swarm, in June, and from the end of September 

 to the beginning of October, in the same nest, in the same year 9 . 



Wheeler writes " At Vaud I had the pleasure of seeing the 

 huge pratensis nest which Forel has had under observation for the 

 past forty years. The colony inhabiting this nest has had a succes- 

 sion of queens during this period, showing that the colonies of these 

 temporary parasites, when once established, may perpetuate them- 

 selves by adopting females of their own species and thus attain an 

 extraordinary age. Just as Professor Forel and I approached the 

 nest at about 10 a.m. on June 5th, the males and winged females 

 were leaving it for their nuptial flight." 41 



On June 3rd, 1906, I took a winged female pratensis at Cor- 

 bridge, in Northumberland, near a rufa nest, and on June llth and 

 12th, 1911, I captured a very few males in, and also away from the 

 nest, at Rannoch, but on July 17th, 1913, when I was in company 

 with Morice, males and winged females were found to be abundant 

 in one nest in that locality 49 , only sex pupae occurring in another. 



The colony founding of pratensis is similar to that of rufa, branch 

 and twin nests occur, and females are received back into the nests 

 after the marriage flight ; and the latter also found their colonies 

 in nests of F. fusca and its races. Wheeler says that in Southern 

 Europe pratensis probably -prefers the var. glebaria of fusca as a 

 host 48 . 



In small pratensis colonies usually only one queen occurs, but in 



