HISTORY OF LITERATURE. 15 



known studies,* which are still one of the principal 

 authorities, probably the most important one, upon the 

 embryology of the Acarina. This paper contains 

 (pp. 490 493) a short chapter upon the embryology 

 of Tyroglyphus siro ; it is far from being as exhaustive 

 and careful as the author's studies of the embryology 

 of the genus Atax (Hydrachnida3) and some other 

 Acari in the same paper, but it is almost the only 

 observation we have upon the embryology of the 

 Tyroglyphidge ; the essential parts of this study will 

 be found abstracted in Chapter VI of this book. 

 Claparede' s study 4 in the same paper, occupying 

 pp. 493 507, is headed " Die Gattung Hypopus Duges 

 als Mannchenform mancher Tyroglyphen." In this 

 Claparede was entirely mistaken ; this also will be 

 referred to in the same chapter of this book under the 

 head of " Hypopial Nymph." This portion of the 

 paper originates the genus Rhizoglyphus, of which 

 Claparede, and Fumouze and Robin were almost 

 synchronous discoverers, and it deals somewhat with 

 the embryology of this creature. 



Donnadieu, also in 1868, published a paper on 

 the genus Trichodactyhis (Dufour). That genus was 

 wholly founded upon hypopial nymphs, and has only 

 hypopial characters. Donnadieu, and all other writers 

 at that time, supposed them to be adults. Curiously 

 enough Donnadieu carefully describes the coition of 

 these creatures, which are immature and devoid of 

 functional sexual organs. Nevertheless Donnadieu' s 

 is a useful and interesting paper, and well illustrated ; 

 it will be dealt with in this book in treating of the 

 genus now known as Trichotarsus. 



P, Megnin, in 1873, published his first paper 

 strictly upon the Tyroglyphidge ; he has been the 

 author of a long series of admirable memoirs on the 

 Acarina, only the more important ones which refer to the 

 family treated of in this book are referred to here. The 



* " Studien an Acariden," in ' Zeit. wiss. Zool.,' Bd. xviii, pp. 445 

 546, pis. xxx xl. 



