174 HORACE DONISTHORPE. 



after the marriage flight had been accepted into a nest of mlxtus. 

 After the natural or violent death of the inixtus queen, the brood 

 of the fuliginosus queen had been brought up by the mixtus work- 

 ers ; the black ants gradually increasing and the yellow dying off 

 little by little, until eventually a pure black colony was left. 



\Yasmann ('09) called attention to the ability of fuliginosus to 

 form new colonies by sending off detachments of queens and 

 workers after the manner of Formica ritfa. He further accepted 

 the interpretation given by Forel and Emery of de Lannoy's dis- 

 coveries, and recalled the fact that he had himself on several occa- 

 sions found mixed colonies of fuliginosus and umbratus. He 

 hoped that future experiment would clear the matter up. 



Crawley ('10) records that in 1898 he frequently found workers 

 of a large bright yellow ant among the workers of a fuliginosus 

 colony nesting in his house near Oxford. He thought at the time 

 that the yellow individuals were workers of flavus, but is now 

 satisfied that they were umbratus. 



Donisthorpe ('10) points out that colonies of fuliginosus are 

 often numerous in a district in which it occurs, and that it partly 

 founds its colonies by branch nests. He mentions that Wasmann 

 had frequently found umbratus nests at the foot of trees inhabited 

 by fuliginosus, and that the queen of the latter had probably 

 founded her colony in the nest of the former. He refers to 

 Crawley's record of umbratus workers in a fuliginosus nest and to 

 his own of 1897. He says he is now convinced that the species 

 was really umbratus; he was not so well acquainted with our ants 

 at the time, but he remembers distinctly thinking how large the 

 " flavus" were. 



Wheeler ('10), when describing an aberrant Lasius from Japan, 

 discusses thoroughly the colony founding of fuliginosus. He 

 writes : " Unlike the queens of the common Lasius niger, the queen 

 of fuliginosus, after fecundation on her marriage flight, and on 

 returning to the earth, is unable to start a colony unaided, and if 

 prevented from rejoining the maternal colony, or a detachment of 

 workers of her own species, has to seek out a colony of L. umbratus 

 and have her young brought up by the workers of this ant. The 

 umbratus queen must be killed either by her own workers or by 

 the intrusive fuliginosus queen, so that the host species is destined 



