176 HORACE DONISTHORPE. 



facts of the experiments by Crawley and himself referred to above 

 (which would have taken up too much space to give in detail in 

 this paper), and records further experiments. "Crawley and I 

 have shown that the female (fuliginosus} does not lay till the year 

 after impregnation, and we have proved her to be a temporary 

 social parasite, as will shortly be seen. . . . D. fuliginosa often 

 founds new colonies by branch nests, which accounts for the fact 

 that many colonies are found in the districts where this ant occurs. 

 After the marriage flight newly fertilized females are received 

 back into the parent and other fuliginosa nests near by. Occasion- 

 ally, however, dealated females are found wandering about in lo- 

 calities some distance from their nests. Forel records finding a 

 number of dealated females on roads at Soleure on July 21, 1869, 

 and Crawley found one at Oddington, near Oxford, about one 

 hundred yards from a nest, and others at Esher in August, 1899, 

 and in such cases as these the females would not be likely to be 

 received back into their own nests. However, when isolated they 

 display no desire to found a colony. Crawley and I have both 

 kept in captivity newly fertilized females which get rid of their 

 wings immediately after impregnation; and they never settle down, 

 but endeavor to escape, and soon perish. 



" Therefore, from the above facts alone, it seems doubtful 

 whether the female of this species can found a colony unaided. 

 But further observations in the field point to umbratus and mixtus 

 as the host species of fuliginosus. In 1897 I found at Lymington 

 a large colony of fuliginosus in a hollow tree, and umbratus was 

 undoubtedly living with it, as workers of both species were going 

 in and out of the same holes. Crawley in 1898 repeatedly found 

 workers of umbratus walking unmolested with the workers of a 

 large nest of fuliginosus established under his house near Oxford. 

 In September, 1900, Tuck sent to me a worker of umbratus taken 

 in a nest of fuliginosus at Bury St. Edmunds. In 1904 de Lannoy 

 found at Knoche-sur-Mer a few workers of mixtus in the midst 

 of a large colony of fuliginosus which were on good terms with the 

 workers of the latter, and in 1906 he again found workers of 

 mixtus in several fuliginosus nests. Forel, Emery, Wasmann, 

 Wheeler, and I commented on de Lannoy 's observations, and ex- 

 pressed the opinion that the presence of these mixtus workers was 



