BEETLE MITES. 225 



CASE he thought, to complete development, so in the same way he mi^ht 



XIII 



find here the brown Hoplophora in the Acarus-like larva. But he 

 found that from the pale-coloured larva a perfect colourless Hoplo- 

 phorus proceeded, within which the intestinal canal retained the 

 same milk-white appearance as in the larval condition. Those 

 which were becoming Hoplophora appeared very light to the eye. 

 The perfect soft animal leaves in this condition the larval skin. 

 All peculiarities of the Hoplophora are visible. The parts are, 

 hoAvever, peculiarly tender. The insect lies for a long time seem- 

 ingly immovable. By degrees the coat thickens, which also 

 becomes firm ; in which it still remains colourless. At first it 

 becomes pale rose colour, then reddish, and at last quite brown. 



The question was thus set at rest. The Acarus-like form and 

 the Hoplophora stand in a genetic relation to one another, 

 and the Hoplophora proceed from the already eight-footed 

 Acarus, showing that that cannot be regarded as an adult mature 

 state. Avery important point remained doubtful, however. In all 

 his experiments several Acari, and these the largest specimens, 

 did not change. How are these individuals to be looked upon ? 

 Perhaps as males. It is very striking that he did not find in the 

 Hoplophora any difference of sex, and that the plurality of indi- 

 viduals contained eggs. Nor could he with any certainty discover 

 anything distinctive of the male sex. The important fact ascer- 

 tained by M. Claparede is, that the Hoplophora goes through an 

 Acarus-like, soft stage, which proves its relationship to the real 

 Acarids (cheese mites, &c.). 



Hoplophora arctata {Riley, 6tli Missouri Report), 



Hcplophora arctata. Copied from Riley's figues. 



