GALL MITES. 347 



CASE similar to those of the Tetranychi. Now the mandible-like objects 

 may be short, stout palpi, but in no other description or figure of 

 Phytoptus that we have seen, is there any sign ever given of them 

 being appendiculated ; indeed they are not represented at all in 

 any highly magnified figure of the head that we have seen. Nor 

 can we find anyone who has seen this. His next argument, that, 

 by compression, a curved, long, narrow blade was made to project 

 from the mouth, requires more ehicidation. His last, that the 

 legs are composed of seven articles, which are proportioned like 

 those of Tetranychus, is erroneous ; the legs of the Phytopti being 

 only composed of five articles. But independent of this alto- 

 gether, there is one fact that seems fatal to 

 the idea of these being Tetranychi, or allied 

 to them. The development of the Tetranychi 

 and Trombidiidse, as well as of their allies Hy- 

 drachnidse and Bdellidae, has been thoroughly Leg of phytoptus. 



' O ^ Copied from Dr. LGu . 



wrought out. Many species have been 

 traced through all their stages, and not one has been found 

 whose early stage has not been six-footed, and very like the 

 mature insect. The Tetranychi and their allies may, therefore, 

 we imagine, be eliminated from the number of possible parents 

 of the Phytopti. 



Next comes M. Scheuten and his Gamasidae. The same objec- 

 tion apphes to his view as to that of Duges. The development 

 of most of the types of Gamasidse is perfectly well known, and has 

 been ascertained to be six-footed in the young, and there is no 

 reason to suppose that those types which have not yet been traced 

 differ from the others in this respect. 



As to the Sarcoptidae again, the outward resemblance to them 

 is much greater than to any other family of mites. Like them 

 the Phytopti have short thick palpi flanking the mandibles. The 

 number of joints in the legs of both is the same. As the structure 

 of the legs is a point of some importance, we may quote Dr. Low's 

 description of those of the Phytopti. " The legs are distinctly 



