GALL MITES. 

 ^ASE reader should see a representation of this curious creature 



339 



The 



accompanying woodcuts shew it respectively as it appears under a 

 moderately strong lens, and under a higher power, and the smaller 

 figure that looks as if it were casting its skin, is a copy of a figure 

 of an individual supposed to be young, given by Professor 

 Westwood. Up to this time it had always been taken for 

 granted, that these mites must be the larvae of some other mite. 

 They had only four legs, instead of the full complement of eight, 



rhytoptus salicis, as it 

 appears when mode- 

 rately magnified. 



Phytoptus tiliK, after Dujardin. 



Young of Phytoptus ribis. 

 Copied from VVestwood's figfure ; 

 possibly only the insect in pro- 

 cess of casting its skin. 



and consequently it was assumed must be larvae. But it was over- 

 looked that no larval form of mite had ever previously been found 

 in which the legs were fewer than six : consequently, if these 

 were larvae, they were larvae of some new type, and the difficulty 

 of placing them was all the greater. M. Dujardin was alive to 

 this; and, on careful examination, he thought he saw, through 

 the semi-transparent skin, appearances of eggs within the body 

 of some of them. He consequently regarded them as a new 

 type of mite which he called Phytoptus. 



If he is right in thinking the bodies he saw to be eggs, the 

 mites must either be fourfooted in their mature stage, or the 

 young must have the power of reproduction before attaining it, 

 a power which no doubt does exist in some types of insects. 

 The woodcut is a copy of Dujardin's figure with the supposed eggs 



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