ON THE LJEE-HISTOBIES OE GA.MASINiE. 297 



Observations on the Life-histories of Gamasince, with a view to 

 assist in more exact Classification. By Albert D. Michael, 

 F.L.S., F.E.M.S. 



[Read February 3, 1881.] 



(Plates XXII. & XXIII.) 



My intention in this paper is to record the results of a series of 

 observations, made during the year 1880, upon the life-histories 

 of a few species of Gamasinse, with the special object of endea- 

 vouriug to decide some of the disputed points in reference to 

 these creatures, which render any thing like knowledge of the 

 family so difficult. 



It will readily be understood how these difficulties arise on the 

 very threshold, when the two gentlemen who have probably paid 

 more attention to the subject than any one else living, viz. M. 

 Megnin of Versailles and Dr. Kramer of Schleusingen, are totally 

 at variance upon such primary matters as whether certain conspi- 

 cuous characteristics are fixed distinctions, affording a good basis 

 for subgeneric and specific division, or whether they are simply 

 marks of an immature stage, which will vanish upon attaining 

 maturity. 



During my late researches into the life- histories of another family 

 of Acarina (the Oribatidse), the results of which are recorded else- 

 where*", I have become strongly impressed with the idea that de- 

 tached observations, on captured specimens, are of secondary value, 

 and that really reliable information upon the subject is only to be 

 obtained by breeding the creatures in confinement,in vessels known 

 not to contain any allied Acarina, and which will afford the means 

 of very frequent observation of the individual specimens which 

 are being traced. Great care and attention, however, is required 

 to keep the creatures alive and healthy under these conditions. 

 It is easy to breed numbers in large vessels containing quantities 

 of shelter and food • but these are of comparatively little service, 

 as the individual specimen is lost sight of. 



It seemed to me that if some of the Gamasids could be bred 

 through their lives, and watched in this manner, several of the 

 questions above alluded to might be set at rest ; but for a long 



* Journal of the Eoyal Microscopical Society, vol. iii. p. 32, 



