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III. — Notes on the Life- Histories of some of the little-knoion Tyro- 

 glyphid^. By A. D. Michael, F.L.S., F.E.M.S., &c. 



(^Bead 14:th January, 1885.) 



Plate III. 



Although the Tyroglyphidse contain many creatures which are 

 generally attractive, from the heauty of the plumes and leaflets 

 with which they are ornamented, and from the general brilliancy 

 of their appearance, when properly disj)layed, yet the genus 

 Tyroglyphus itself is not one which includes any species likely to 

 become favourites with slide-collectors from the elegance or singu- 

 larity of their external forms ; it is, however, a group the members 

 of which obtrude themselves unpleasantly upon human notice, 

 through their extreme destructiveness of animal and vegetable 

 matters which are useful to man, either as food, medicine, or other- 

 wise, and of his zoological and other collections. The common 

 cheese-mite, T. siro, is the well-known type of the genus, and indeed 

 it has been taken most frequently as the type of the whole of the 

 Acarina ; although, to most persons acquainted with the order, it 

 may seem about as easy to typify it as to have a type Insect. 

 T. entomologicus is the terror of entomologists, and the general 

 feelings of the genus Homo towards the genus Tyroglyphus are 

 decidedly hostile. Under these circumstances it is pleasant to find 

 a member of this ill-reputed genus put forward on high authority 

 as the friend and ally of man, if that view can only be supported. 

 Some years ago a serious alarm arose in America at the extent 



EXPLANATION OF PLATE III. 



-Tyroglyphus corticalis, male, dorsal view, x 140. 



„ „ „ ventral view, x 140. 



„ „ female, dorsal view, x 140. 



„ „ „ ventral view, x 140. 



„ „ nymph, side view 



„ „ Hypopus, dorsal view. 



„ „ „ ventral view. 



„ „ „ fully formed within the skin of the 



inert ordinary nymph. 

 -Tyroglyphus corticalis, egg, x 100. 



„ „ right mandible of female, X 350. 



„ ,, labium and other mouth-organs, X 300 



„ „ first leg of female, x 250. 



„ „ tarsus of second leg of female, x 500. 



„ „ sucker-plate. 



-Rhicoglyphus Robini, Hypopus, dorsal view, X 100. 



„ „ „ ventral view, X 100. 



„ „ „ sucker-plate, x 300. 



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