360 ants' nests. 



in Lasiiis fuliginosus the glands of the upper jaw are extraor- 

 dinarily large, and conjectured that they are the glands which 

 secrete 'this viscous substance (cement). In fact, a comparative 

 physiological study of this gland which Wolff (" The smeUing 

 organ of bees ") erroneously designated as the smelling-mucous 

 gland, shows that a discovery which has been misinterpreted by 

 Wolff is of special value. 



The substance secreted by this gland, both in bees and in ants, 

 and also the secretion of the posterior glands of certain ants (the 

 DoUchoderides, with whom it serves as a weapon for smearing the 

 faces of their enemies), is immediately decomposed at the first 

 contact with the air, with a violent production of gas-bubbles and 

 the development of an aromatic odour which is very peculiar. As 

 soon as this chemical decomposition is completed, the residue of 

 the secretion is transformed into a resinous, viscous mass, w^hich is 

 very sticky. There is no doubt in my mind that the viscous sub- 

 stance formed in this way is not a smelling mucus, as Wolff, by a 

 very farfetched explanation, which is untenable for many other 

 reasons, would have it, but forms the cement with which the nests 

 and many other things are welded together. 



What is still too little known, however, is the manner in which 

 a genuine phylogenetic evolution converts this gland cement 

 gradually into spun threads. The pasteboard of Lasius fuligino- 

 sus^ Latr., is very rich in wood dust or earthy matter and very poor 

 in cement, so that it is very brittle. There is a drawing of it in 

 my Fourmis de la Suisse^ PI. II., Figs. 32 and 2)2>' The pasteboard 

 which Liometopwn 7nicrocephalu?n^ Pz., manufactures in the inner- 

 most hollow of venerable but, nevertheless, strong, handsome, 

 hard, large trees, and which is also composed of wood dust, is 

 somewhat less brittle. They make it in oaks, poplars, apricot 

 trees, etc., in south-eastern Europe. Mayr gives a drawing of it, 

 taken from a photograph, in the Proceedings of the Imperial Royal 

 Zoological and Botanical Society of Vie?ina^ June i, 1892, Vol. 

 XLII., PI. v.. Fig. 7. A great many species of the genera Cre- 

 mastogaster, Lund, and Dolichoderus^ Lund, build only pasteboard 

 nests on the boughs of trees, and these nests vary very much in 

 their nature. In some cases the pasteboard is harder and more 

 brittle, resembling wood, as among the species just described ; in 



