
368 A CHAPTER ON MITES. 
known regarding the metamorphoses of a few species of 
mites. But a French naturalist, C. Robin, has recently 
observed in certain bird sarcoptids, to which the parasite 
of the Downy Woodpecker noticed above is allied, a still 
“more complicated series of phenomena; in these the males 
pass through four, and the females through five stages, in- 
dieated as follows: (1) the egg, on issuing from which the 
animal has the form of (2) a Aexapod larva, followed by 
the stage of (3) óctopod nymphe [four-footed pups], with- 
out sexual organs. (4) From some of these nymphs issue: 
a, sexual males, after a moult which is final for them; 5, 
from others issue females without external sexual organs, re- 
sembling the nymphe, but larger, and in some species fur- 
nished 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 numer- 
ous than the changes of condition." “The larve undergo 
from two to three moults before passing to the state of - 
nymphis." These latter also undergo two or three moults. 
(Annals and Magazine of Natural History, 1868, p. 78.) 
In some other species of mites no males have been found, 
and the females have been isolated after being hatched, and 
yet have been known to lay eges, which produced young 
without the interposition of the males. This pa 
sis has been noticed in several species. 
With their rapid increase in numbers these insects often 
suddenly appear in vast numbers on various articles of food, 
. and about houses, so as to be very annoying. Mr. J. H. 
z Gregory, of Marblehead, Mass., has found the mite figured 
. on plate 6, fig. 6 (magnified 60 diameters), very injurious 
: e : (do the seeds at the cabbage, which it sucked dry. This is an 
ting form and. appears to belong to the genus Che- 
It 



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| is of medium size, and especially noticeable from 

