ants' nests. 381 



Fig. 13.— Cross section of a fragment of a nest of Colohopsis truticata, 

 Spinola, excavated in the wood of a dead, but extremely hard 

 pear tree. Found by me at Vaux, Canton Waadt, Switzer- 

 land. Four-thirds natural size. C/t., Excavations of the 

 nest in the wood. B., Bark of the bough of the pear tree. 

 0., Opening of the nest outward, and head of a soldier of 

 Colobopsis trnncata, who is guarding this opening, or, rather, 

 who is keeping it closed with his head, as with a stopper. 

 The soldier is standing in the egress passage, which is seen in 

 cross section. W., Two workers of Colobopsis truncata, one 

 in the nest, the other outside, hurrying to the entrance, 

 where the soldier, drawing back, wdll make room for him for 

 a moment. 



,, 14. — Cross section of the pseudo bulb of Hydnophytum montanum, 

 received from Java through Dr. A. Frick, of Zurich. Photo- 

 graphed one-third of the natural size. The stalk, the leaves, 

 and the root of the plant are also seen (see text). 

 ,, 15. — Pasteboard nest of Dolichoderus bituberculatus, Mayr, on the 

 bough of a tree. Received from Bangkok, Siam, from the 

 late well-known turner, Mr. Sigg, of Zurich. In order to 

 show the interior labyrinth, a portion of the nest has been 

 removed by a fiat, perpendicular cut. Photographed one- 

 third of the natural size. Surf., Surface of the cut and inner 

 labyrinth. U.S., ^Natural upper surface of the nest. Br., A 

 small branch of the main bough, cut through and inclosed in 

 the nest. The nest rests upon the main bough. 

 >) 16. — Web of Polyrhachis spinigera, Mayr, from Poonah, India ; 

 received from Mr. Wroughton. Microscopic enlargement ; 

 Hartnack, System IX. (Compare Fig. 8, Gesp.) 

 ,, 17. — Nest-wall of Polyrhachis jerdonii, Forel, from Ceylon ; 

 received from Major Yerbury through Mr. Wroughton. 

 Microscopic enlargement ; Hartnack, System VII. FL, Small 

 flakes of vegetable matter. fVeb, Spun net of the ants, by 

 means of which these flakes are joined together in a web. 

 »» 18. — Apiece of the nest pasteboard of Dolichoderus bispinosus, 

 Oliv. , from tropical America ; received through Professor 

 Emery. Microscopic enlargement ; Hartnack, System IV. 

 Fib., Vegetable fibres of Bombax ceiba, L., of which the nest 

 pasteboard is composed. Cem. , Ant cement or lac, by which 

 the vegetable fibres are glued together or fastened (of a bright 

 yellowish or brownish colour). Mesh, Empty meshes left by 

 the nest walls between them. 



j» 19. — Represents a " soldier " standing at the door of egress. 

 See text, p. 357. 

 N. B. — All the figures, except Fig. 8, were drawn or photographed 

 (Figs. 14 and 15) from nature by Mr. L. Schroter. I myself only drew 

 Fig. 11 and the ants in Fig. 10. 



The originals of Figs. 1, 2, 3, 4, 7, 10, 14, 15, IG, 17, and 18 are in 

 my collection ; those of Figs. 5, 6, 9, 12, and 13 are in the entomolo- 

 gical collection of the Museum of the Federal Polytechnikum (my 

 former collection of European ants' nests). 



