298 MB. A. D. MICHAEL ON THE 



time I was not as successful iu rearing the Gainasinae as I had 

 been with the Oribatida?. The former are far more active crea- 

 tures, and did not thrive when confined in the small glass cells 

 which I had used for the latter, and which are so handy for obser- 

 vations. I have at last succeeded in keeping the several species 

 which I have attempted in good condition, and rearing them 

 several generations, by using very large cells, and small round 

 glass dissecting-troughs, each being covered by a flat plate of glass 

 with two or three small holes in it, each hole being covered with 

 very fine muslin gummed outside the glass, the cover being larger 

 than the cell, and the holes in such a position that they can either 

 be made to come over the interior of the cell so as to ventilate 

 it, and allow the escape of moisture, or pushed beyond the cell- 

 wall leaving the moisture confined. This arrangement, combined 

 with a curtain, and, what is more important, care and frequent 

 attention, enabled me to regulate the light, temperature, and 

 hygrometric condition of the air in the cell, so as to obtain in each 

 instance what was most suitable to my captives. They finally 

 became apparently quite at home and contented in their prisons, 

 not attempting to escape when the cell was sometimes uncovered 

 for the use of higher powers : this is a great point, because habits 

 cannot be observed when the creatures are excited and endeavour- 

 ing to escape. 



One very doubtful point had to be decided at the outset, viz. 

 what the Gramasinae really fed upon, as they manifestly could 

 not be successfully reared unless supplied with proper food. 

 Megnin says* they are nourished on the liquid products of the 

 decomposition of dead vegetables or the excrements of quadrupeds 

 and birds ; and he proceeds to cite the places where they are found 

 as proof of this assertion. He is also decidedly of opinion f that 

 the nymphs and females do not obtain any nourishment from the 

 insects upon which they are so constantly found, but simply use 

 them as a means of conveyance. Kramer also states^ that damp 

 and decaying vegetation are the necessaries of their existence. 

 I did not find, however, that the Gramasids which I attempted to 



* " Meraoire sur l'organisation et la distribution zoologique des Acariens 

 de la fainille des Gainasides," Eobin's Journ. de l'Anatoinie et de la Physio- 

 logie, May 1876, p. 325. 



t Loc. cit. p. 290. 



\ " Zur Naturgeschichte einiger Gattungen aus der Fainilieder Gamasiden," 

 Archiv fur Naturgeschichte, 1876, erstes Heft, p. 47. 



