140 A. C. OUDEMANS. ACARI. 



Tyroglyphus longior when pregnant, seldom is globular, but occasionally really occurs in such 

 a form, as if blown up with water. Generally the tarsi are longer than genu and tibia to- 

 gether, but seldom they are so long as delineated by HERMANN; yet BERLESE, 1884, and 

 CanESTRINI, 1888, hâve drawn such tarsi. It seems that there are several varieties, or muta- 

 tions. The tarsi are drawn in two pièces, a mistake also made by TURPIN in his drawing of 

 Acarus horridus, and caused by a hair attached at the ventral side of the tarsus. It is true 

 that the médian pair of hairs in the foremost part of the abdomen is drawn long, whilst in 

 reality it is short, and that three other pairs of short hairs are not drawn, but HERMANN 

 has not been always accurate in his drawings e. g. the chelae are drawn smooth, whilst in 

 reality they bear three teeth on each finger. Moreover Tyroglyphus longior may be often 

 found in mosses, and hère often females are swollen in such a manner as drawn by HERMANN. 

 The colour of the legs is said to be whitish or yellowish, a fact often occurring in Tyroglyphus 

 longior. It seems to me that HERMANN, who does not mention the locality where his mite 

 has been found, found it in France, most probably near Paris, where he was a student. 

 1806. LATREILLE only quotes the name of the mite. 



18 17. LATREILLE only quotes the name of the mite. 



18 18. Olivier reproduc.es only Hermann's figures. 

 1829. LATREILLE only quotes the name of the mite. 

 1834. DuGÈS tells us of this species as follows: 



„Nous dirons quelques mots encore de Y Acarus dimidiatus d'HERMANN, que j'ai observé 

 réellement, et qui m'a servi à confirmer une partie des observations que m'avait fournies son 

 congénère" (this is Aleurobius farinae, described by him on the foregoing page), „telle que 

 l'existence d'un corselet distinct" (at présent we say céphalothorax or prosoma), „le rappro- 

 chement central de l'insertion des hanches" (hère he evidently means only the coxal plates 

 of legs I and II), ,,la forme en pince des mandibules, déjà bien connu d'HERMANN et assez 

 bien représentée dans ses planches, et de plus la lèvre palpigère qui lui a échappé. Les palpes 

 soudées offraient quelques poils en dehors. Le bec était fléchi en dessous ; la 4 e paire de pattes 

 aussi grêle que la 3e; le dernier article de tous" (hère he means the paratarsus) „présentait 

 une conformation bien remarquable ; la caroncule était sessile arrondie, pellucide, et il en 

 sortait une seule griffe ou crochet mobile, et très recourbé, bien plus fort que ne sont ordi- 

 nairement les deux ongles des acariens parasites; HERMANN a donné de cette disposition une 

 mauvaise figure, mais qu'il est facile de corriger d'après ce que je viens de dire." 



It is clear that DUGÈS examined a species perfectly resembling the Acarus dimidiatus 

 of HERMANN. He therefore does not say anything of the number and length of the hairs, 

 so that wc may adopt he has really examined Tyroglyphus longior Gervais. Moreover he 

 found it in old cheese, a well known habitat of the named species. Of course he found it 

 in France. 



1836. LATREILLE only qnotes the name of HERMANN's mite. 



1841. KOCH describes and delineates a mite, which cannot be other than Tyroglyphus 

 longior Gervais. He , it is true, describes only two hairs in the posterior half of the 

 céphalothorax, whilst in reality there are four, but how easily KOCH may hâve overlooked 

 the other two ! The two longitudinal folds on the dorsum are seldom to be observed in the 

 species, but BERLESE, 1884, draws them too. KOCH, better than HERMANN, mentions that 



