ants' nests. 379 



find the mighty mounds of Formica rufa, exsectoides, and exsecta^ 

 frequently gathered into large, united kingdoms, containing many 

 nests (polycalic colonies), and also the tree nests of Lasius 

 fuliginosus, L. brwineus, Camponotus herculeanus, Lmnetopum 

 microcephalum, etc. Genuine — that is to say, free— tree nests of 

 pasteboard or web in the boughs of trees do not occur in Europe. 

 Lastly, in the forest clearings, the edges of the woods, and in 

 thickets we find a rich mixture of the three above-named land- 

 scape types with respect to ants' nests. The meadow type, the 

 forest type, and the detritus or declivity type are here mingled 

 pell-mell. 



The nest structure in the desert, as I have been enabled to 

 learn by observation in southern Tunis, forms a peculiar type. 

 There all is excavated in the sand. There are neither mounds nor 

 stones, but at most hillocks of sand around the openings of the 

 nests. 



My object has been merely to give, by the aid of drawings, a 

 clear view of our present knowledge of the nest-building of the 

 ants and to communicate some new facts in connection with it. 

 I trust that I have succeeded. 



To conclude, it is a pleasure to me to express my warmest 

 thanks to my friend, Mr. Ludwig Schroter, for his successful draw- 

 ings ; to Professor Schroter for his kind assistance, his suggestions, 

 and his advice ; and to the persons who procured me my excellent 

 materials, especially my friends, Mr. Wroughton, Dr. Frick, Pro- 

 fessor Emery, Dr. Liengme, and Professor Mayr. 



EXPLANATION OF PLATES XIX. and XX. 



Fig. 1.— A gall, inhabited by Polyrhachis qerstdckeri, Forel, from 

 Delagoa Bay, South Africa; collected by Dr. Liengme. 

 One-sixth less than the natural size. A, The gall from the 

 outside ; op. , the egress opening of the gall producer, used 

 by the ants. B, Longitudinal section through the gall, show- 

 ing the cavity and its filling of web and a half partition. 

 ,, 2.— Longitudinal cross-section of the stalk of Solanum auricnla- 

 tum, from Antananarivo, Madagascar, inhabited by Techno- 

 myrmex alhipes. Smith ; collected by Pere Chamboue. The 

 marrow of the stalk has been divided by the ants into 

 chambers. Two-thirds natural size. 



