DONISTHORPEA. 229 



effectually continued and wellnigh completed by the little people, 

 who had shown their wisdom in utilising the decaying wood and 

 fine comminuted particles, which it had doubtless accumulated by 

 its mandibles, which acted as sharp saws, to fashion its many 

 chambers and accommodate the countless numbers of the rapidly- 

 increasing family. In fact the tree measured ten feet ten inches in 

 circumference ; its centre, to the height of four feet six inches, was 

 tenanted by a formic population of unnumbered thousands. The 

 rich, brown, honeycombed, finely-wrought woody material occupied 

 a space of about one foot four inches in diameter." 25 



Adlerz writes in his recently published book on ants : " Besides 

 L. fuliginosus only one other ant was known in our part of the 

 world, Liometopum microcephalum, which builds carton nests of 

 somewhat more fragile quality in old decaying oaks, poplars, and 

 apricot trees in S.E. Europe. But it is now proved that another of 

 our species of Lasius, the yellow L. umbratus, has the same 

 habit in Nordland. This species, which resembles our small, usually 

 yellow, mound ant, but is larger and of a clearer yellow, builds in 

 stumps, among roots, under stones, its carton nest of the same black 

 colour as L. fuliginosus, but with stronger walls. This species also 

 cultivates the fungus Cladotrichum (possibly a different species from 

 myrmecophilum) on the walls of the cells, thus increasing their 

 solidity. The carton which these two species of Lasius manu- 

 facture is more fragile and brittle than that which is used as 

 building material in the nests of many tropical ants " 65 . Wasmann 

 has recently shown that the European Donisthorpea emarginata 01., 

 also makes carton [Biol. Centralb. 33 264-266 (1913)]. 



I sent several samples of D. umbrata carton from different 

 localities to Dr. Jessie Baylis Elliott, and after obtaining cultures 

 and making a careful study of the fungus this carton contains, she 

 has decided it is a new variety of Hormiscium pithyophilum which 

 she has called H. pithyophilum var. myrmecophilum. Dr. Baylis 

 Elliott tells me umbrata carton might almost be considered a pure 

 culture of Hormiscium, and fuliginosa carton a pure culture of 

 Cladosporium. 



I have seen the winged sexes in numbers in the nests in July, 

 August, and September, and the winged female in some numbers 

 in a nest at Wey bridge in December. Hamm found many winged 

 females in a nest in the Museum grounds at Oxford in April, and 

 Forel records the male in nests in Switzerland in June 14 . 



Andre gives July to September for the marriage flight 20 and 

 Saunders, August to September 30 . 



Forel saw many males in the streets of Zurich on August 22nd, 

 1868 14 , and he noticed the same sex leaving the nest, before men- 

 tioned, at Munich in immense numbers from five to seven o'clock in 

 the afternoon at the end of July, 1875 15 . 



Tuck records the winged forms at Cromer in August, 1902 38 , 



