GALL MITES. 341 



CASE and the supposed perfect form a Gamasus. These are here shown. 

 But, beyond the fact that he found these mites at times in the 

 vicinity of each other, one within the gall and the other without 

 it, he gives no explanation how he arrived at his conclusion. 

 To be sure, we cannot expect very close evidence of the progress 

 of development in such minute ani- 

 mals ; but something better than mere 

 contiguity or proximity should be given. 

 There is not even similarity or analogy 

 in any of the parts. He thinks, indeed, 

 that he saw the half-developed larva, 

 and gives a figure of it, which we here 

 copy; but the reader will see that this FigureofaHypopus.badiy drawn. 



Supposed by Scheuten to be the un- 



is only a badly seen and badly drawn '^^'^ copied ftomsciTeuten-s^^^^ 

 figure of a Hypopus. 



It is to be remarked, however, that in another species, called 

 by him Flexipalpus tiliae, which he observed on the lime trees, 

 not in the nail-gall, but in a rust, or Erineum, on the under side 

 •of the leaves, named Erineum rubigo, there is a certain outward 

 similarity of appearance between the larva and what Scheuten 

 calls the perfect insect, as may be seen in the woodcuts ; but here 

 we agree with Claparede in thinking that this is merely a badly 

 figured and badly described Tetranychus of the lime tree. We 

 shall return to the consideration of, whether these mites are really 

 the perfect form of the Phytopti, presently ; but we must not omit 

 his objection to Dujardin's notion that the rounded bodies, visible 

 under the skin of the Phytopti, were eggs. He objects that 

 Dujardin's only evidence that ova were in them was that he 

 saw roundish structures shining through the skin of the animal. 

 ^* Even with transmitted light," says he, ^' a very indistinct view 

 of the interior can be obtained ; and this is shown by his own 

 figure. In this we see what he regards as eggs, but no trace 

 of other viscera, for which, however, there is plenty of space." 

 In the interior of his larvae, on the other hand, various rounded 



