OR LIFE-HISTORT OF OERTAIK ACAEIKA. 385 



beyond the body (PL XV. figs. 3-4) ; the abdomen, however, pro- 

 jects behind this carapace, and is decidedly segmented, a most 

 exceptional thing in adult Acarina, although sometimes found in 

 larvae. The first leg is much enlarged, and is provided with a 

 great, single, holding-claw, exactly like Donnadieu's Trichodactylii^s 

 Xylocopice, but, oddly enough, the second and third legs have 

 didactyle claws, like Dufour's figure, which was considered an 

 error. The fourth leg is terminated by long setae, as in Hypopti/S, 

 TricJiodactylus, &c. 



When this account appeared I, like its discoverer, imagined it 

 to be a Sypopus, and I have ever since been desirous of investi- 

 gating its life-history, greatly with the view of assisting to decide 

 the Hypopus question. It was not, howevei', until the spring of 

 the present year (1883) that I succeeded in obtaining healthy 

 living specimens in sufiicient numbers to enable me to carry out 

 the research. This year, however, partly from my own captures 

 of humble-bees, and partly from the supplies of living specimens 

 sent me by that excellent collector Mr. E. Bostock, of Stone, I 

 found myself in a position to pursue the subject. 



Mr. Greorge apparently regarded liis so-called. Hypopus as 

 strictly a parasite of the Gamasus which lived on the bee, not as 

 a parasite of the bee itself I, however, soon found, when I had 

 an ample supply of material, that quite as many existed on the 

 bee as on the Q-amasics : my first hope therefore was that I 

 might keep the bee alive with the whole united-happy-family of 

 Oamasidce, Hypopi, &c. I was unfortunately entirely unable to 

 do so under any conditions which would enable me to watch such 

 small creatures as the Hypopi ; I therefore had to abandon this 

 idea, and limit my ambition to keeping alive such Gamasids as 

 bore Hypopi, which I knew that I could do. In the meantime, 

 however, I had found several solitary specimens of the supposed 

 Hypopus in moss, where I was searching for Oribatidse ; these 

 were not parasitic upon any thing, and it therefore struck me that 

 possibly the Hypopi might live in a cell without any host, 

 tried, and found that they lived very well for a considerable time; 

 and, as hereinafter stated, I ultimately found that, when I had 

 discovered suitable food, they lived quite as well without any host 

 as with one. I did not employ any of the Hypopi found in moss 

 for my investigations, for fear of confusion of species, but con- 

 fined myself strictly to those found on the bee or on the Gramasidse 

 infesting it. 



