22j 



HARDWICKE'S SCIENCE-GOSSIP. 



which it now descends with safety to its enclosed 

 harbour, has rendered the water-spider one of our 

 most amusing and interesting aquarium pets. 



For several years it has been my pleasure to keep 

 a few of these along with a variety of other, though 

 select life in the aquaria. With newts or fish they 

 seem perfectly agreeable, as one of the latter, a 

 coloured fish {Cyprinus aurattis) almost ten years old 

 in the aquaria, to the surprise of all, made itself 

 especially an associate, and playmate with its Crus- 

 taceous companions. 



In a small tank, thickly beset with Ranunculus 

 diversifolius, Helosciadium inundatum, and Lenuia 

 polyrhiza, with its broad fleshy fronds, and long spread- 

 ing roots covering the surface, the whole thus formed 

 a most suitable habitat, in which, for special observa- 

 tion, I placed several water-spiders, which I collected 



yellowish mass of egg surrounded with a glistening 

 layer of air, distinctly separate from its still unfinished 

 harbour. 



After a day or so of rest, it further extended the 

 nest downwards, in a bell or funnel form, until 

 nearing two inches long ; then closed the lower or 

 wider portion, with the exception of two openings, 

 one on each side, just to give leave of its exit or 

 admission. 



This being completed, the mother could often be 

 seen gracefully wending her way to the surface, and 

 carrying down large successive bubbles of air, then 

 carefully liberating, one by one, in order to form a 

 sufficient supply, in which it then remained for some 

 days. 



From the end of the first week the egg now 

 gradually grew darker, and on July 1st, exactly the. 



Fig. 87.— Male of water-spider {Argyroneta aquatica). 



on the 5th of June, while out collecting aquatic plants. 

 One, apart from the other, appeared to be somewhat 

 restless ; this of course was watched with anticipation, 

 as the others had already made themselves at home. 

 For the first two days it quickly traversed from side 

 to side, making repeated attempts to climb the glass 

 to effect an escape, but eventually it settled down, 

 and was soon busily webbing together in a diverging 

 manner the pectinate leaves of the water crowfoot ; 

 then going within its leafy shade, not only as it 

 almost appeared to do, to examine or to arrange the 

 work so far done, but actually to weave its silken 

 cocoon, or nest, in which, on the fifth day, 10th of 

 June, through a small opening it had left unwebbed 

 from it closing on the sides of the glass, and which 

 fortunately served the agreeable purpose of pursuing 

 the future progress of what could be observed, the 



third week, the upper portion of the nest, or 

 cocoon, was completely laden with young ; when,, 

 the large globule of air slowly began to diminish, and 

 on being exhausted, the mother seemed reluctant to 

 find a further supply, as though she had done 

 her duty. 



Here the young naturally became troubled, and 

 in the fourth week were quickly parading the 

 interior of their cell, apparently for escape, which 

 they, through the course of nature, effected on July 

 nth; thus, in about thirty days, over forty young 

 were actively playing their delightful and youthful 

 part, each bearing its silvery bubble, thus assuming 

 the respective and peculiar characteristics of the 

 parent. 



The water-spider has its own instinction and 

 acutencss, in repelling its aggressors, especially so 



