16 



sodden by undue exposure to the wet. I have noticed, in cases 

 where water spiders have been kept without an opportunity of 

 leaving the water, that they have eventually succumbed, and even 

 the temporary refuge of a leaf or piece of cork is not sufficient. 

 These spiders leave their watery haunts at times, it would seem, for 

 hygienic as well as hunting purposes. An interesting little notice 

 from the Rev. O. Pickard-Cambridge's " Spiders of Dorset " (vol ii, 

 p. 471) may be quoted. He once kept, he writes, a male spider of 

 this species for three years in Durham ; and every night this spider 

 came out and wandered about the room. It came to an untimely 

 end, as it was found one morning in a dying condition. 



As a parallel case, I need only refer to the well-known fact that 

 tUg hirsute covering on the thorax and abdomen of a beetle like 

 Hydrous piceus will, in time, lose its gloss and air-retaining power; 

 and the same applies again to Hemiptera like Notonecta glauca. 



But a unique feature comes before us for our study, when we con- 

 sider this air-breathing organism, as not only passing the greater part 

 of its existence under water, but as emerging from ova laid and 

 hatched in a silken chamber of captive air. The development of a 

 spider being merely one of growth, without transformations, there is 

 not, of course, as in some insects, e.g. the Odonata, any adaptive 

 larval or pupal form with respirative processes suitable for sub- 

 aqueous life, until the great change takes place to the airy flight 

 of the imago. The water is, to Argyronefa, merely a surrounding 

 medium through which it passes, and in which it lingers and works, 

 as a diver might carry on his avocations under the sea. In either 

 case, the very element in which occupations are carried on is the 

 one from which danger is to be feared, and from which, as far 

 as respiration is concerned, no aid but only destruction is to be 

 expected. 



The little water spider, at birth, not only finds in its little dome 

 all the life-sustaining properties of an airy chamber into which it at 

 once enters from the egg, but it has around it a supply from which 

 it can freely draw and carry away round itself all that it needs for its 

 passage through the water, and to which it can return for further 

 supplies. It is evident that without the air carried into the nest by 

 the mother before she lays her eggs, there would not only be no 

 medium in which the young could live, but also no means of obtain- 

 ing any protection in the first journey for surface-air. The alternative 

 would be that the eggs might be laid and hatched on dry land ; but 

 then the habits of Argyroueta would be entirely altered, becoming 

 more like those of Dolomedes or Pirata, and no longer entitling her 

 to the distinct epithet '''■ aquatica." 



Before passing on from this part of the subject, I should like to 

 draw attention to an apposite little paragraph which caught my eye 

 in the January number of " Knowledge " (1904) : " At the Meeting of 

 the Zoological Society Mr. R. L. Pocock called attention to some 

 Australian spiders (of the genus Desis). They live in crevices of 



