250 



ARACHNOIDEA. 



CASE Hypopus MUSCARUM {Linn.). See figure on page 234. 

 XIV. 



On flies. 



Hypopus alicola {Duj.). 



On the wing of a bee. 



No. 3. II Hypopus musc^ (Acarellus muscce, Tatem., 



Monthly Micr. Journ. 1872, pi. xl, 263.).— 3. 

 Magnified sketch of ditto, copied from Mr. 

 Tatem's figure. 



An elongate form, like H. alicola Duj. 

 Duj ar din obtained his specimen from the 

 humble-bee; Mr. Tatem his from a small 

 dipterous fly. 



No. 4. ^^ 0^W^M Hypopus pulicis (Acarellus pulicis, Tatem, loo. 



cit. ). — 4. Magnified sketch of ditto, copied from 

 Mr. Tatem's figure. 



Found by Mr. Tatem in " the abdominal 

 cavity of a dead flea." It comes very close 

 to Hypopus lasvis of Dujardin, the chief 

 difference seeming to be that its posterior pairs of legs are scarcely 

 quite so robust ; but as Mr. Tatem mentions that these legs were 

 only visible through the skin, and not yet free, it may be that his 

 specimen, not being yet closed, was not perfectly developed, 

 and that the legs might afterwards have become somewhat 

 stronger. We have already alluded to the significance of the 

 locality in which it was found by Mr. Tatem. 



Hypopus alicola. 

 Copied from Dujardin. 



Hypopus filicum {Duj.), See figure on page 235. 

 On the fronds of Celerach officinalis. 



Hypopus arvicola {Duj.). See figure on page 236, 

 On the field-mouse. 



