276 BRITISH ANTS. 



rarely under stones. It does not like the neighbourhood of human 

 habitations, and is fast disappearing from the heaths round Bourne- 

 mouth, being driven away by building operations. The nests of 

 exsecta are smaller, and are built of much finer materials than are 

 those of rufa, being chiefly composed of grass arid ling, but fern 

 fronds, and bits of other plants, and sometimes a few pine-needles 

 and other vegetable refuse are used a typical exsecta nest can be 

 recognized at a glance. 



In 1907 Butler swept a single exsecta worker in Parkhurst Forest, 

 Isle of Wight 29 , and, having told me whereabouts he thought he 

 had taken it, on April 26th, 1909, I visited the locality in company 

 with Taylor, and this spot having been drawn blank, we went 

 further into the forest, when I found a small deserted nest, which 

 I at once recognized as that of exsecta, and a little further on we 

 came upon a very suitable situation for this species, being a clearing 

 planted with young fir trees, when we immediately found four in- 

 habited exsecta nests. A large nest near, which from its construction 

 and materials had evidently belonged to exsecta was found to be 

 inhabited by F. rufa, either the former having deserted, the latter 

 had occupied this old nest, or else the latter had forcibly taken 

 possession 34 . 



These nests are dome-shaped, or sometimes somewhat conical, 

 their size about that of a football, seldom more than eight or ten 

 inches in height, and often smaller. Galleries are excavated in the 

 earth beneath the hillock, and when the latter is built over gorse, 

 or tough grass-roots, etc., the nest is very difficult to dig up 

 thoroughly, in consequence of which dealated females are not often 

 obtained. Two or more nests will often be found close together 

 I have found two nests so situated by the side of a road over the 

 moor at Aviemoor, two large nests side by side near a path at 

 Braemar, a number of nests near each other at Bournemouth, and 

 in Parkhurst Forest four or five nests may be found in one clearing, 

 several at intervals along a ride, and others scattered all over the 

 Forest I have counted over twenty nests in one day there. 



Isolated nests often occur, and when a nest has grown to a large 

 size, some of the workers will migrate with a young queen to a new 

 situation near by. 



Forel mentions an immense colony of F. exsecta he found in a 

 clearing at the foot of Mont Tendre 11 , consisting of more than two 

 hundred nests occupying a radius of over one hundred and fifty 

 metres ; all the nests being connected with each other by paths, 

 and all the ants in the different nests on friendly terms with one 

 another. 



On the other hand, in Wasmann's experience, isolated nests are 

 more usual with this ant, he neither saw in Vorarlberg and Tirol, 

 nor in Rhineland and Westphalia nests connected with each other. 

 He found that single nests belonged to single colonies, and that at 



