2 24 ARACHNOIDEA, 



CASE bending the head down upon the under side, so that when it 

 chooses it can, hke some beetles, retire entirely into its shell and 

 shut it up, looking then like a tiny, oval, brown speck, without 

 head, legs, or any other members visible. Claparede found this 

 little creature in the burrows or borings in rotten fir wood ; but 

 he also sometimes found in them, but rarely together, another 

 larger, semi-transparent, soft, white mite, like a cheese mite. The 

 idea which would naturally occur to anyone would be that this 

 might be the larva ; but then it had eight legs, and therefore 

 it was assumed must be a perfect insect ; and, moreover, by 

 watching the hatching of the eggs deposited by the Hoplophora, 

 Claparede soon ascertained that, as usual, the first stage was a 

 six-footed soft white mite, bearing a close resemblance to the 

 eight-footed, soft, white Acaroid form. What relation did the 

 latter bear, then, to the Hoplophora with which 

 it was associated ? M. Claparede solved this by 

 the following experiment : He took twenty speci- 

 mens of the soft white Acaroid mite, and placed 

 them upon a morsel of decaying pine wood, first 

 taking care to see that there were no other mites 

 present. He then put the wood in a moist flask, 

 Hoplophora contractiiis ^hich hc allowed to reuiaiu undisturbed for three 

 cilpar^desfigure."' wceks. Aftcr that time he took the wood out of 

 the flask. The mites were scarcely to be seen. 

 They had penetrated by boring, and he had to dig them out. On 

 examination he found only twelve specimens resembling Acarus 

 against seven Hoplophora. A transformation of seven had thus 

 taken place, and one individual was missing. However, the nature 

 of the transformation was not yet clear. He repeated the experi- 

 ment in which he, at the same time, included a larger number of 

 specimens. So he followed the traces of the transformation. His 

 researches into the development of Hypopus, of which we shaU 

 presently have to speak, suggested to him that as its colourless 

 Tyroglyphus-like larva enclosed a brown Hypopus on its way, as 



