FORMICA. 279 



Forel captured an incomplete lateral ergatandromorph in a 

 wild colony in Switzerland, which he briefly described : 



Worker with some portions of the left side male. Stature of ordinary 

 worker. Male portions : a longitudinal black band under the head, left half 

 of pronotum, a large V-shaped black blotch on mesonotum, a black protu- 

 berance (scutellum ?) and vestiges of alar articulations. All the rest worker. 

 Epinotum malformed. 10 



Forel states the eggs are late in appearing and gives May 6th as 

 the first date 14 , but, in captivity at any rate, the females lay earlier 

 than that Wasmann records that a female in a colony in his 

 possession laid eggs in February, larvae being present in March 31 , 

 and eggs were laid in my observation nest in the latter month. 

 Worker cocoons are present in the nests up to late in the year. 

 As we have seen, new exsecta nests are established and a colony 

 spreads by means of branching, etc., some young queens are 

 retained in the nests, and others would be accepted back after the 

 marriage flight into the different nests of a large colony. 



Young females of F. exsecta, however, also found their colonies 

 in nests of F. fusca, and as the exsecta female is smaller in com- 

 parison with her workers than is rufa being smaller than large 

 fusca females and dark in colour, she is more readily accepted into 

 the fusca nests ; mimicry playing some part in the matter. 



The reason why no very early stage of a mixed colony (a female 

 exsecta, and fusca workers only) has been observed in nature is 

 probably that an exsecta queen would easily be overlooked 

 among the fusca workers, but later stages of mixed colonies have 

 been found in September, 1867, Forel discovered in a wood near 

 Apples a very small mixed colony of F. exsecta var. rubens and 

 F. fusca 13 ; on April 26th, 1870, Bugnion found a mixed colony of 

 exsecta and fusca near Lausanne, and in the following year at 

 Ormonts another of exsecta- pressilabr is and fusca under a stone 13 . 

 In October, 1906, Wasmann dug up at Luxemburg an exsecta-fusca 

 colony in a simple earth nest of the fusca type, containing an 

 exsecta queen, several hundred exsecta and fusca workers, and 

 pupae of the former, but no fusca female was present 31 . 



On May 27th, 1910, I found an isolated nest on the borders 

 of a wood at Bournemouth, of the usual exsecta type but very 

 small, and on being examined it proved to contain both exsecta 

 and fusca workers, the latter being in considerably greater 

 numbers. It was impossible to properly dig up the nest, on account 

 of the presence of gorse roots, etc., in the ground, and no female 

 was found, but here undoubtedly was a new exsecta colony, founded 

 by a young queen of that ant, which had entered a fusca nest, and 

 been accepted by the inhabitants 37 . On August 26th, 1911, 

 Hamm also found a mixed colony of exsecta and fusca at Bovey 

 Tracey, in Devonshire 43 . 



Some of the F. exsecta nests found by me in Parkhurst Forest, 



