ants' nests. 491 



The nest of the PoXyrhachis jerdonii^ Forel whicli I received from 

 Ceylon through Major Yerbury is very interesting. This species builds 

 upon leaves small nests, the wall of which greatly resembles in appear- 

 ance the shell of many Phryganeidce larvai. Pebbles, and esi)ecially 

 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 color. Fig. 17 gives a microscoijic picture of 

 this nest wall. We see here unmistakable small fragments of jjlants 

 (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 calling in the aid of the still more maguilied 

 web of PolyrhacMs dives Sm. (also from the East Indies), in tig. 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 nuu;li thicker, 

 of a brown color, is produced by Polyrhachis spinif/erCt Mayr. Fig, 16 

 presents a microscopic picture of it. Here we find no more crosspieces, 

 but only silk threads. They are, however, still irregular, of varying' 

 thickness, spun across each other into a web. This web is fixed in a 

 wonderful manner in the ground, where it forms the lining of a funnel- 

 shaped cave, which is widened out into a chamber at the bottom. The 

 honor of the discovery of this highly interesting nest is due to Mr. 

 Wroughton; he found it in Poonah, India. Mr. L. Schroter made the 

 somewhat schematic drawing of the nest, in its natural position, from 



' Polyrhachis jerdonii (workers) n. sp. 4| millimeters in length, short and broad; 

 related to the rolyrhachis argentea Mayk, but still shorter, without silvery down, 

 with a much less arched thorax sharply edged at the side, the abdomen sharply 

 edged in front, with red mandibles, anteuuie, and legs (except the tarsi). The oth(U' 

 parts are of a dull black, thickly and irregularly punctate-reticulate, and witli 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 tlaps in 

 front, not carinate; the laminfe diverge behind. The scape of the short frontal 

 antenna- is somewhat in the shape of an S, and hardly extends beyond the l)ack 

 of the head. Scales between the spines, with a convex, emarginated upper border. 

 Spines Just like those of Pohirhachls argentea. The sculpture <»f the head is like the 

 meshes of a net, with a dotted background. The body is dotted like a thimble. 



