Jan. 1, 1869.] 



HARDWICKE'S SCIENCE-GOSSIP. 



and also numerous Cheyleti, Avhich bad so freely 

 imbibed tbe contents of the bodies of tbe Der- 

 manyssi as to acquire tbeir colour, — a very deep red, 

 almost black. 



These remarks would be extremely incomplete 

 if no allusion were made to the species of Cheyletus 

 that Mr. R. Beck described, and which I have lately 

 been fortunate enough to find. The three or four 

 specimens which came in my way had taken up their 

 abode on the cover of a book that had lain in a 

 cupboard for about a year undisturbed. They were 

 each sitting on the top of a small heap of eggs in 

 various stages of development, some being already 

 hatched, and some only just laid. At short dis- 

 tances off, also, on all sides, there were numerous 

 cast skins of the creature, and discarded remnants 

 of unlucky acari that had fallen a prey to them. 



Fig. 4. Retribution on a Cheyletus by a Cheese-mite. 



The most remarkable and interesting discovery 

 in connection with this Cheyletus was the fact that 

 he obtained several generations from the first indi- 

 vidual, without the intervention of a male, leaving 

 the question, "whether the creature is really her- 

 maphrodite, or whether, as with Aphides, one act 

 of fertilization by the male produces an indefinite 

 series of generations ? " to be decided by some 

 expert microscopic physiologist in the future. 



He says, " On July 10th of this year, a young 

 acarus of this species was taken from a trap, in 

 which there was only a mature female; it was 

 completely isolated, and on the 29th of the same 

 month it laid eggs, which hatched on the 4th of 

 August. One of these on the day it was hatched 

 was removed to a trap, and also completely isolated ; 



by the 13th of September it had laid eggs, and some 

 had hatched. On the 19th of September, two of the 

 young from the last-mentioned trap were separated 

 and secured. Since then, one of these specimens was 

 killed ; the other laid eggs, which hatched on the 

 29th of December, and one of these young ones is 

 still alive, but isolated in the same way as its pre- 

 decessors. 



" The securing a succession of three generations, 

 including some accidents, has with me extended 

 over a period of about five months, and I am quite 

 prepared to admit that the proof of agamic repro- 

 duction in this acarus would have been more 

 satisfactory if continued through a longer period ; 

 but after reading Professor Huxley's paper on the 

 Agamic Reproduction of Aphis, in part of which 

 he states that c in Myriapoda and Arachnida the 



Fig. 5. Mr. R. Beck's Cheyletus. 



process is not known,' I have thought that the 

 few facts I have just given were of sufficient value 

 to bring before your notice." * 



This Cheyletus has shorter legs than the other 

 that I have alluded to in the early part of my notes ; 

 it has a smoother skin, and its palpi and head are 

 much larger relatively to the rest of its body. It 

 also is of a paler yellow ; but it is possible that the 

 colour may be greatly influenced by its diet. The 

 first pair of legs are more highly developed as 

 organs of locomotion than in the other species, but 

 it appears, notwithstanding, to be less given to roam- 

 ing about. As it has been in my possession but a 

 few days, I have not been able to verify the obser- 

 vations of the distinguished microscopist I have 

 quoted; but at some future time I may be able to 

 communicate further information. 



S. J. MTntire. 



* Journal of Microscopical Science. 



