NOTES ON DRAGONFLY PARASITES. 245 
grown, colourless at first, but usually reddish or reddish-brown 
in later life. Unless they are placed immediately in a preserva- 
tive fluid, however, they quickly lose both their colour and 
rotundity. We have always noticed that mites occur most 
plentifully when their Zygopterid hosts are but newly on the 
wing, and it would seem that dragonflies rid themselves of their 
parasites to a great extent as the season advances. We have, 
however, a mite-attacked male of H. cyathigerum taken at the 
Black Pond, Surrey, as late as September 3rd. It would also 
seem that some larve leave the egg much sooner than do others, 
for we have met with teneral specimens of P. nymphula early in 
May and teneral examples of EH. cyathigerum towards the end of 
July carrying larve in the same colourless and ungrown condi- 
tion. Although, as we have seen, locusts are weakened and even 
killed by the attacks of parasites, there is no evidence before us 
of injury done to Odonata in this way. 
The occasional presence of mites upon Odonata was known 
so long ago as 1778, when De Geer figured and described red 
parasites from the thorax of a small dragonfly under the name 
Acarus libellule, and identified them with the A. gymnopterorum 
of Linneus. By these and other old writers they were regarded 
as adult forms, but it was subsequently recognised that these 
six-legged creatures were larval forms which in later life acquired 
the fourth pair of legs proper to Arachnida. As we have seen, 
Krendovsky called some larve from the wings of an Anisopterid 
dragonfly Arrhenurus papillator, and, following him, Mr. Soar 
considered parasites from the bodies of such dragonflies as Agrion 
pulchellum and A. puella to be no other than Arrhenurus globator. 
We have made several enquiries with a view to clearing up the 
doubts which still exist respecting the affinities of dragonfly 
parasites with other larval Hydrachnide, but we have failed to 
elicit any definite information, owing to these parasitic stages 
being so little understood. Three species of Zygopterides with 
mites attached to their bodies were submitted for examination 
to the eminent Hydrachnologist, Herr I’. Koenike, of Bremen. 
He has kindly informed us that the parasites belong to ditferent 
species of Hydrachnide, but to the same genus. At present he 
is unable to say with certainty into which genus the larve fall, 
but in any case he does not agree with those authors who have 
referred them to Arrhenurus. Attempts made by Herr Koenike to 
rear dragonfly parasites have not been successful, but he has bred 
the real larva of A. globator, and he is satisfied that the parasites 
in question have nothing whatever to do with Arrhenurus larve. 
It was suggested by McLachlan that the parasites may 
attain their position on the body or wings of a dragontly by 
climbing up the legs of their host while it is at rest. This 
suggestion, in itself a likely one, is rendered the more probable 
by the fact that in our experience of Zygopterides the mites 
