150 BETTISH TYROGLYPHID^E. 



different account of its mouth-organs from what other 

 writers had described in Hypopus ; he stated that it 

 had maxillae divided into two equal parts and placed 

 between three-jointed palpi. Fiirstenberg's figures 

 clearly show that he was dealing with an ordinary 

 hypopial nymph, not a homopial one. As to the 

 supposed mouth-organs, it can only be said that 

 Fiirstenberg had a talent for imaginary mouth-organs ; 

 for in his most laborious and magnificently illustrated 

 work every species is drawn and described as having 

 two pairs of chelate mandibles, a thing never yet 

 found in any known Acarus. Fiirstenberg carried his 

 measurements to the fourth place of decimals of a 

 millimetre (in 1861) ; he however recognised that the 

 creatures were probably immature. 



Claparede in 1868 was the next contributor to the 

 literature of Hypopus ;* he is entitled to the credit of 

 being the first person to connect Hypopus in an intelli- 

 gent manner with Tyroglyphus^ although Grervais had 

 classed them together without assigning any reason. 

 Claparede found upon potatoes, dahlia tubers, and 

 cabbage-stalks, near Geneva, what he considered to be 

 a new species of Tyroglyphus. He had it in great profu- 

 sion, and kept up his observations upon it for three years. 

 He bred it upon hyacinth bulbs in his study in large 

 numbers ; he said it belonged to the genus Tyroglyphus 

 and called it T. Dujardinii or Hypopus Dujardinii, 

 usually the latter ; but, as he imagined, he never found 

 a male ; all his specimens were females according to his 

 view. Claparede never found any Gramasids amongst 

 them, but he did constantly find large numbers of 

 Hypopi all of one kind ; moreover he actually saw 

 some nymphs of the supposed Tyroglyphus, which greatly 

 resemble the adult female, cast their skins and produce 

 a Hypopus, not an adult female Tyroglyphus as other 

 nymphs of the same species did. He never could see 

 any eggs in a Hypopus nor any vulva. Claparede's 

 observations were absolutely correct ; but he drew from 



* " Studien ;xn Acariden," in ' Z. wiss. Zoo].,' Bd. xviii, pp. 493507. 



