1910 EXTOMOLOGICAL SOCIETY. 53 



most of them attacking the Lasii as soon as they emerged from the nest. A few 

 young, less than ten, were brought to the surface, as they emerged, and immediately 

 returned to the nest. The queen remained in the nest throughout this battle. The 

 time occupied in driving the Lasii into their nest was about fifteen minutes. After 

 they were driven in, a number of the Myrmicas — -about 20 — remained at the en- 

 trance as before, the last of them leaving the entrance fourteen minutes after the 

 battle proper closed. 



On the night of August 20th-21st, the Lasii were enticed out near to the 

 Myrmica nest in the same manner as before. Their presence was discovered 

 by two Myrmica workers which alarmed the nest. The Myrmicfe, in appearing 

 on this occasion, did not bring their young with them, but among the last of the 

 ants which came pouring from the entrance, the queen appeared. The Lasii were 

 at once attacked and driven away from their captures and in about fifteen minutes 

 were all driven into their entrance. The queen Myrmica remained on the surface 

 not more than two minutes; her presence there was probably accidental. It is 

 possible that she was caught in the swarm of workers emerging and carried along 

 with them. She took no part in the battle, not going more than an inch from the 

 entrance to her nest. The Myrmics on this night did not remain at the Lasius 

 entrance more than two minutes after the last Lasius had disappeared. 



On the night of Aug. 22nd-23rd, the drawing out of the Lasii and the 

 emergence of the Myrmica workers was exactly the same as on the previous nights, 

 excepting that the queen did not appear. No young were brought to the surface 

 by the Myrmicse on this occasion. The Lasii were driven from their food and 

 into tlieir nest in approximately the same time as on the two previous nights. 

 After the Lasii had all disappeared the Myrmicae scarcely remained at their entrance 

 at all, returning to their own nest almost immediately. 



On the night of Aug. 23-24th we had an exact duplicate of the proceedings 

 of the previous night, until the battle was well under way, when we drew out the 

 second and smaller nest of Lasius. By using insects which they were particularly 

 fond of we drew them up to the rear of the line of fighting Myrmicae, about as 

 near the Myrmica nest as the first nest of Lasius had been when the Myrmicae 

 attacked them. When this second nest of Lasius came near so that the Myrmicae 

 began to notice them the last of the large nest of Lasii were disappearing. The 

 appearance of this second nest seemed to demoralize the M3rrmic8e, which were 

 already in some disorder, and instead of attacking, as we expected they would, most 

 of them ran around the cluster of Lasii and disappeared into their nest; a few 

 of them attacked the Lasii, but not being supported, fell off and returned to the 

 nest, leaving the second nest of Lasius in full possession of their insects, which they 

 dragged to their nest. 



On account of the nights becoming suddenly colder, we could not get Lasius 

 to come out, and so had to discontinue the observations. One of the most 

 curious things was the apparently regular battle formation of Myrmica. In every 

 case, soon after the conflict began the Myrmicae would form in a somewhat irre- 

 gular line, with only a few workers behind, and a few in front of this line, those 

 behind fighting with the straggling Lasii, and those in front being attacked by 

 several Lasii and seldom moving, simply allowing the Lasii to pull at them. The 

 line was always thickest at the centre, and thinnest at the ends where the Lasii 

 were least numerous. The ends in all cases advanced faster than the centre, so 

 that towards the end of the battle the line would assume the shape of a horseshoe. 

 On the night of the 23-24th when we brought up the second nest of Lasii behind 

 this apparent formation, which was already partially broken up in driving the 



