78 Miscellaneous. 
The pond in which this was found is a very small one, only 5 or 6 
yards in diameter, and the only other species I have met with in it 
is Lophopus crystallinus ; of the latter I have not met with any this 
year. This variety grows attached to twigs in the full blaze of the 
sun; and the little animals appear to enjoy it immensely. The speci- 
men I obtained was about four inches long, by an inch thick in the 
middle; but I left another about the same length but apparently 
thicker. 
I am, Gentlemen, 
Yours obediently, 
Devon and Exeter Institution, Epwarp Parrirt. 
Exeter, June 18, 1868, 
On the Avicolar Sarcoptide, and on the Metamorphoses of the Acarina. 
By C. Rosin. 
The Acarina pass through a series of metamorphoses—a hexapod 
larva issuing from the egg becoming converted into a nympha, from 
which the adult Mite proceeds, The author has observed in the 
Sarcoptide a more complicated series of phenomena; in these the 
males pass through four, and the females through five stages, indi- 
cated as follows :— 
1. The egg, on issuing from which the animal has the form of 
2. A hexapod larva, followed by the stage of 
3. Octopod nymphe without sexual organs, 
4, From some of these nymphee issue :—a, seaual males, after a 
moult which is final for them ; 6, from others issue females without 
external sexual organs, resembling the nymph, but larger, and in 
some species furnished with special copulatory organs. 
Finally, after a last moult following copulation, these females 
produce 
5. The sexual and fecundated females, which do not copulate, and 
in the ovary of which-eggs are to be seen. No moult follows that 
which produces males or females furnished with sexual organs; but 
previously to this the moults are more numerous than the changes 
of condition. 
Ovular and embryonal state.—The eggs of these Acarina are of a 
cylindroid form with rounded ends, one of which is smaller than the 
other, and corresponds with the rostrum. They are more or less 
flattened on one side; and to this surface the ventral surface of the 
young animal corresponds. The exclusion is effected by the division 
of the cephalic extremity into two halves. The ova are deposited 
by the avicolar Sarcoptidee in the angle formed by the barbs with 
the stem of the feather. In general the segmentation of the vitellus 
has not commenced when the eggs are laid ; but in some species the 
vitellus is divided into four lobes while the egg is still in the oviduct. 
The division takes place in planes perpendicular to the greater axis 
of the vitellus. 
The Larva.—In all the species the larve are hexapod; and the 
arrangement of the epimera shows that it is the third, and not the 
