1885-86.] Edinburgh Naturalists' Field Club. 297 



VII.— DISCOVERY OF THE WATER-SPIDER {ARGYRONETA 

 AQUATIC A) NEAR BALERNO. 



By Mr A. B. HERBERT. 



(Read Dec. 18, 1885.) 



When the Club visited the bog at Bavelaw last summer, we had 

 not sufficient time to thoroughly investigate the locality; so on the 

 4th August, a bright and warm day, I went with some of my chil- 

 dren for a further search, both for wild plants and also objects for 

 a fresh-water aquarium. The peat-pits on the bog contain thou- 

 sands of Frogs and Tadpoles in the early spring. The Dytiscus mar- 

 ginalis we have also found there, and the larvas of the large Dragon- 

 fly ; and it was while searching for the latter, by drawing out some 

 Myriophyllum from one of the pits, that I saw a Spider creeping 

 on the moss, which I at once recognised as the Argyroneta aqua- 

 tica. Further investigation brought to light many specimens, in 

 various stages of growth, of this peculiar species of the Arachnidas ; 

 and on the surface of one of the pits, floating on the Myriophyllum, we 

 observed several white silken bags, about the size of a filbert, which 

 proved to be the Water-spiders' nests, and full of very minute young 

 ones. These, in this early stage of life, are quite white. Three of 

 the full-grown Spiders I sent by post to a scientific friend in Lon- 

 don, who informed me they were all females. At home I at once 

 established, at a cost of tenpence, a small Spider aquarium, con- 

 sisting of a confectioner's glass, 9 inches high by 4 inches in dia- 

 meter, with perforated zinc top, in which I placed a few sprigs of 

 Anacharis from the Canal, and the Spiders have lived in this jar 

 from the 4th August to the present time. My difficulty with the 

 Spiders was not knowing their natural food. There were among 

 the Anacharis many minute forms of animal life, such as small 

 Crustacea and Coleoptera, but I cannot be certain that the Spiders 

 ever fed upon these. My first attempt at feeding was with a Blue- 

 bottle fly ; and the Spider's proceeding with this was interesting 

 to watch. He placed the fly down among the weed, then spun a 

 single thread of web to the surface, and, running up this, he brought 

 down a bubble of air and fixed it in the weed ; then up again for 

 another supply of air to add to the first — -these journeys, voyages, 

 or divings being repeated till the air-bubble was of considerable 

 size, and dome-shaped. He tlien fetched the fly and pushed it up 

 from below into the air-bubble, and then, placing himself inside 

 with the fly, remained quiescent for some time, no doubt feeding 

 on his prey. The Spiders, I find, will eat flies, gnats, and ear- 

 wigs, but are not very partial to the last. They seem to lie 



