96 



PSYCHE. 



[June-Sept. 1S94. 



in which a number of species were fig- 

 ured and described under the name of 

 Hypoderas^ n. g. In a note some time 

 later Giebel ('63) acknowledged the 

 identity of Nitzsch's genus Hypoderas 

 with Hypodectes Fil., which had been 

 brought to his attention and which 

 might justly claim priority. In this 

 note Giebel criticizes the plan of Filippi 

 in naming the species after the host 

 since, as Nitzsch emphasizes, the same 

 species may be found in more than one 

 host and, on the other hand, the same 

 host may h:)rbor more than one species 

 of the parasite. 



Robertson ('66) published a short 

 account of the discovery of a mite para- 

 sitic in tlie English pigeon, but he 

 appears to have been entirely ignorant 

 of the work of his predecessors, except 

 Montagu, whom he quotes. He gives 

 a short account of the anatomy of the 

 mite, recognizes it as an imperfect form, 

 remarks upon its evitlent relationship to 

 the Sarcoptidae and announces his in- 

 tention of pursuing the subject further, 

 a purpose which seems never to have 

 been fulfilled. 



Gerstacker ('67) makes a brief men- 

 tion of Robertson's work and identifies 

 this mite as a species of Hypodectes 

 Fil.* 



A full account of the anatomy and 

 histology of Hypodectes coliimbae, ti. 

 sp. is to be found in Slosarsky ('77) -t 

 In this paper, read before a congress of 

 Russian naturalists at Warsaw in 1S75, 



♦The species which Robertson examined is said by 

 Megnin ('79, p. 131) to be the same as Filippi's Hyf^o- 

 decies nycticoracis. 



t On the authority ofMegrnin ('79)- 



the author adds a new species to tlie 

 genus Hypodectes Fil. He found no. 

 internal structure at all except the 

 narrow muscle bands just under the 

 cuticula by Vvfhich the movements of the 

 body and appendages are effected. 

 Further than this the interior of the 

 body consisted of a granular vesicular 

 mass in which cell structure could not 

 be demonstrated.* 



To the researches of Megnin is due 

 the greater part of our knowledge of the 

 life history of this form. In a series of 

 papers ('73-'79) he established the 

 larval nature of a number of mites 

 without mouth-pnrts whicli had previ- 

 ously been regarded as distinct genera, 

 and showed them to be merely abnor- 

 mal ( ?) stages in the life history of 

 other known species. With Ch. Robin 

 (Robin et Megnin '77) he investigated 

 among others the form found in the 

 pigeon and showed it to be an abnormal 

 (adventitious or "hypopial"t) nymph 

 of Plerolichus falciger Megnin. 



* In sections cut last spring I was equally unable to 

 find either nuclei or cell walls in this granular mass. 

 Claparede ('6S) has shown that the metamorphoses of 

 the Acarina are not simply ecdyses, but that the body 

 undergoes an extended hystolysis. 



t Hypopial, adj. derived from Hypopus. Mt^gnin ('73, 

 p. 493) says "The conclusions to be drawn from my 

 observations is that the genera Hypopus, Homopus and 

 Trichodaciylns, and the numerous species which have 

 been established as subdivisions of those genera, must 

 be stricken from our zoological nomenclature. The 

 word Hypopus may be retained, but only as a common 

 name serving to designate the curious cttirassdi , 

 heteromorphons and adventitious nymph of the Tyro- 

 glyphi whose office is the preservation and dissemina- 

 tion of the species to which it belongs." The name was 

 afterwards used by the same author for similar nymphs 

 in other families, e. g. Pterolichus (Robin et Megnin, 

 '77. P- 403)- 



