SUGAR MITES. 277 



CASE ixiite are smooth like bristles, or feathered, or downy, but it is 

 nevertheless a most reliable character, as is the little terminal 

 projection at the tail and the velvety skin. Sometimes the one 

 or the other may be in a position where they cannot be seen, but 

 two out of the three present and the third doubtful is generally 

 sufficient warrant to say that the bearer is a Glyciphagus. If seen 

 in life they are at once known by the rapidity of their movements, 

 they run ; the Tyroglyphi walk or creep. The hairs are a most 

 extraordinary part of their structure, for it is not only in downy 

 hairs that the deviation from normal hairs shows itself, but in the 

 most wonderful feathered and flat pennate transparent spatula- 

 like plumes with a transparent membrane uniting the side and 

 midribs. These different types of hair structure enable the 

 genus to be separated into two sufficiently marked sections, 

 the one having long • downy hairs and very swift in their 

 motion, the other short feathered or membranous pennate 

 plates, and comparatively slow in their motions. At least two 

 of each are well described ; but there are also a number more 

 of the first section which have been less satisfactorily described 

 although they may be good species. 



Section T. 

 Body somewhat elongate, and with long downy hairs. 



No. 17. Glyciphagus prunorum {Hewing, Nov. Act. xviii.). — 17. Enlarged sketch 

 of ditto, copied from Hering's figure. 



Hering's description and figure is not sufficiently minute in its 

 details to allow us to be sure of his species, but as it was the first 

 described, and if we were sure about it, ought to be its type, we 

 have placed a copy of it in the case. 



Found by Hering in dried plums preserved in sugar. The 

 sugar merchants and grocers in this country are sometimes 



