APR 10 1917 
ea) 
THE OTTAWA NATURALIST. 
VoL. XIX. OTTAWA, AUGUST, 1905. No. 5 
THE EGGS OF THE SCARLET WATER-MITE ( Aydrachna 
sulcata ). 
By Prof. E. E. PRincE, Dominion Commissioner of Fisheries, Ottawa. 
The Scarlet Water-mite (ydrachna) is common in ponds 
and ditches near Ottawa. On account of its conspicuous color- 
ation it may be readily seen moving actively through the water, 
or climbing amongst green water-weeds in search of feod. Its 
eggs and spawning habits do not seem to have been described, 
and in a number of papers on the Acarines or Mites, which I have 
looked over, I find no reference to its ova. Some of the memoirs 
which I have consulted (including Edouard Claparéde’s splendid 
contribution entitled ‘‘ Studien an Acariden,”* with ten exquisite 
coloured piates), describe and figure the ova and early stages of 
‘several allied species; but none of them quite agree with the eggs 
of Hydrachna sulcata, which I here describe. I have mounted 
some of the adults and the ova, in order that I may finally deter- 
mine them later, as Dr. Wolcott reported to Professor H. B. Ward 
_that in certain Michigan waters no less than 43 species of 
Hydrachnide, belonging to 16 genera, had been obtained in 
18937; and, as our Ottawa region is probably no less prolific, the 
diagnosis of specimens demands very careful examination. Owing 
* to the limited amount of work done in the study of mites, any ob- 
servations upon them, however fragmentary, are of interest. As 
the Rev. O. P. Cambridge has said, the study of the mites, on 
account of their small size and obscure modes of life, seems to 
have been neglected ; yet, the variety which characterises their 
* Zeitschrift fiir Wiss. Zool. Band 18, 1868. 
+ Michigan Fish Comm. Report 1896, p. 15. 
