DONISTHORPEA. 207 



Schenck found the winged sexes as early as June 25th, 1852, at 

 Nassau 11 , and he says the marriage flight takes place from the 

 beginning of July to the beginning of September 10 . Forel gives 

 the middle of July to the middle of August 26 , and Crawley records 

 marriage flights at Seaton on July 14th and September 15th, 1912 61 . 

 I have found the winged sexes in the nests from July to September, 

 but I once found a male on April 26th, 1913, under a tin on the 

 sand-hills at Tenby 63 and I noticed a marriage flight at Woking on 

 September 26th, 1912 60 . On August 5th, 1906, Hamm captured a 

 female nigra with short wings a mermithogyne at Bovey Tracey 

 in Devonshire. 



The marriage flight takes place in the afternoon, and the follow- 

 ing description of one I observed at Folkestone on August 9th, 1911, 

 will serve to illustrate the method adopted by the species of 

 Donisthorpea whose males are considerably smaller than the 

 females. 



A large colony of D. nigra occurred in one of the pillars of a gate- 

 way to a house in a street in the town, the ants entering the masonry 

 by a hole in the mortar at the base of the pillar. At five o'clock 

 in the afternoon the workers were much excited, running all over 

 the pavement and up and down the pillar, and a few winged ants 

 were out, going in and out of the entrance to the nest. At six 

 o'clock thousands of males and winged females appeared, emerging 

 from the hole, swarming all over the pillar, and climbing to the 

 top, and on the railings and shrubs in the garden. A few couples 

 were observed in copula, and these flew away together, but most 

 of the winged ants flew off separately, rising straight into the air, 

 and going up so high that they .were lost to sight. The workers 

 helped some of them to start, tapping them with their antennae, 

 and pushing them to the edge of the top of the pillar. More females 

 than males occurred. By 6.25 P.M. nearly every winged ant had 

 disappeared, and some few females were already on the ground 

 without wings. 



A marriage flight of this species was observed by two of my 

 friends on the same afternoon as the above, at Margate, and Sea- 

 view in the Isle of Wight. On August 28th I noticed a marriage 

 flight at Dover, and on my return to Folkestone the same afternoon 

 another was seen there 59 . Marriage flights of D. nigra occurred at 

 Weybridge, Putney, Walton, Chobham, and Camberley on August 

 10th, 1914 (and also of D. flava, D. umbrata, and Myrmica ruginodis 

 at the first-named locality). 



Huber says it is requisite that the temperature of the air should 

 be at the 15 or 16 Reaumur (67 F.) to allow of our witnessing the 

 departure of the males and females 8 . 



It is evident that the ants are affected by some atmospheric 

 influence which probably extends at the same time over a large 

 area. Eaton records D. nigra swarming in the Cactus-house in the 



