vn] WATER-SPIDERS 51 



tent of a female and sets up his own establishment- 

 generally somewhat smaller close at hand, filling it 

 with air in the approved manner. He then builds a 

 sort of corridor uniting the two domes, and when this 

 is complete he bites through the female dome, thus 

 uniting the two air reservoirs by means of a connect- 

 ing tube. Not seldom it happens that the female is 

 in no mood for dalliance, and a battle royal ensues, 

 with disastrous results to both domiciles and the tube 

 that connects them. The male, however, is in this 

 case well able to hold his own, for he is larger than 

 the female, a phenomenon elsewhere unknown in the 

 spider realm. Argyroneta lives for some years, and 

 makes two diving-bells each year one near the 

 surface in summer and one at a greater depth in 

 winter. It was thought at first that one was con- 

 structed especially for receiving the eggs and the 

 other as a habitation, but the egg-cocoon may be 

 found in either, for there are two broods in the course 

 of the year. The winter dome is of very dense silk, 

 glossy in appearance, and giving the effect of a uniform 

 sheet of silky material rather than a fabric. More- 

 over its mouth is closed, and the spider remains 

 inactive within. It is this winter domicile that is 

 most frequently found in the shells of molluscs. The 

 egg-cocoon is also dome-shaped, having a convex 

 upper and a flat under surface. The newly hatched 

 young inhabit their mother's tent for a time and then 



42 



