British Orihaiidse. By A. D. Michael 39 



in the water, and which seemed to be a nymph of one of the 

 Orihatida'. I secured a sketch of the creature, and endeavoured 

 to breed it to the perfect form, but I was not successful ; and as I 

 have great hesitation about putting forward any theory relying 

 upon a single specimen, I held my tongue about it, hoping to 

 investigate the matter further. This year I returned to the 

 locality, and discovered my old friend in Sphagnum, and again 

 attempted to breed it through, but without success; the search 

 after this acarid, however, revealed two other nymphs, both 

 apparently those of Oribatidse; with these two I was more 

 fortunate, and, notwithstanding the difficulty presented by their 

 aquatic residence, I was able to trace their life-histories ; with 

 them I found two adult species, one of which unquestionably 

 belonged to the typical genus Orihata, although somewhat modified 

 from tbe land species, the flexible wing-like expansions of the 

 abdomen being far less developed, and seeming as though they had 

 a tendency to become abortive, but all the characters of the genus 

 are clearly developed. This Orihata I subsequently ascertained 

 was the perfect form of one of my nymphs ; I found plenty of it, 

 and succeeded in breeding several : as far as I can ascertain, it is 

 unrecorded, and I propose (if that be the case) to call the species 

 O^'ibaia sphagni ; the adult is figured at Plate IV. Fig. 6, and the 

 nymph at Fig. 7 ; the full description will be found in the second 

 part of this paper. The nymph is sluggish, and lies concealed in 

 the narrow part of the Sphagnum leaf near the point, and conse- 

 quently is difficult to detect, and far from easy to observe in a state 

 of nature when detected ; neither this, nor any of the aquatic or 

 amphibious species which I have found, are free-swimming 

 creatures, nor is their organization such as to enable them to do 

 so ; they crawl on the Sphagnum and aquatic weeds, chiefly the 

 former, usually on the submerged parts, their mode of life remind- 

 ing me greatly of the Halicurid^e found in the sea crawling upon 

 Hydrozoa, although the Ortbatidie are vegetable, and the Hcdi- 

 caridiG probably animal feeders. 



It might naturally be supposed that the second adult would 

 turn out to be the mature form of the second nymph, but this was 

 not the case ; I have a suspicion that it is the mature form of the 

 nymph whioh originally attracted my attention, but as I have 

 hitherto failed to breed it, this suspicion remains unconfirmed. I 

 have not figured or described it in this paper. 



The history of the second nymph is an interesting one to mo, 

 but, in order to explain wherein that interest lies, I fear I must 

 mako a short digression. I have before stated that the larva^ and 

 nymphs of the OrihatidiB are usually soft and light-coloured, the 

 adults being hard and dark ; the adults vary in hardness and dark- 

 ness according to species and genus, chiefly by genera, and where 



