ants' nests. 363 



from Ceylon through Major Yerbury, is very interesting. This 

 species builds upon leaves small nests, the wall of which greatly 

 resembles in appearance the shell of many Fhryganeidce larvae. 

 Pebbles, and especially small fragments of plants, are cemented 

 together by a fine web or woven together, and form a rather soft 

 and tough web-like nest wall of a bright greyish-brown colour. 

 Fig. 17 gives a microscopic picture of this nest wall. We see 

 here unmistakable small fragments of plants (Schol), bound 

 together in a web by peculiar silk threads (Gesp). These silk 

 threads are found, upon a closer examination, to be of very 

 irregular thickness, often branching, and in many cases issuing 

 from a thicker crosspiece. Upon calUng in the aid of the still 

 more magnified web of Polyrhachis dives, Sm. (also from the East 

 Indies), in Fig. 7, there can be no doubt that a viscous substance 

 secreted by the glands, similar to that which we have seen used as 

 glue by the ants previously described, is here simply drawn out 

 into threads. In Fig. 7 are seen the thicker crosspieces of a still 

 more shapeless mass of cement and the more finely spun threads 

 drawn transversely out of them. 



Polyrhachis dives, however, no longer needs any foreign 

 material. It makes its nest wall out of pure silk web, exactly 

 like coarse spun yarn or the web of the caterpillar. The web is 

 of a brownish yellow, and is fixed between leaves, which are lined 

 with it and bound together. Mr. Wroughton, of Poonah, India, 

 sent me such a nest, simply between two leaves. 



A still finer, softer silk web, finer and thicker than the finest 

 silk paper, very soft and as pliable as the finest gauze, though much 

 thicker, of a brown colour, is produced by Polyrhachis spinigera, 

 Mayr. Fig. 16 presents a microscopic picture of it. Here we 



the tarsi). The other parts are of a dull black, thickly and regularly punctate- 

 reticulate, and with very fine, yellow, sparse, recumbent, and almost no erect 

 hair. The head is wider than long, and broadens out very much behind. The 

 clypeus is short, without flaps in front, not carinate ; the laminae diverge 

 behind. The .scape of the short frontal antennce is somewhat in the shape of 

 an S, and hardly extends beyond the back of the head. Scales between the 

 spines, with a convex, emarginated upper border. Spines just like those of 

 Polyrhachis argentea. The sculpture of the head is like the meshes of a net, 

 with a dotted background. The body is dotted like a thimble. 



