
366 A CHAPTER ON MITES. 
a few mites are injurious to man, the larger part are bene- 
fieial, being either parasitic and baneful to other noxious 
animals, or more directly useful as scavengers, removing 
decaying animal and vegetable substances. 
e transformations of the mites are interesting to the 
philosophie zoélogist, since the young of certain forms are 
Fig. 62. remarkably different from the adults, and 
in reaching the perfect state the mite 
passes through a metamorphosis more 
striking than that of many insects. The 
young on leaving the egg are usually 
hexapodous, č. e., have six legs, as we 
have seen in the case of the Zvodes albi- 
pictus previously noticed in the Natu- 
RALIST (Vol. ii, p. 559). Sometimes, however, as in the 
case of the larva, as we may call it, of a European species, 
Typhlodromus pyri (Pl. 6, fig. 4), the adult of which, ac- 
cording to A. Scheuten, is allied to Acarus, and lives under 
the epidermis of the leaves of the pear, there are but two 
pairs of legs present, and the body is long, cylindrical and 
worm-like. Plate 6, fig. 5 represents the four-legged larva 
of another species of Typhlodromus. 
We have had the good fortune to observe the different 
stages of a bird mite, intermediate in its form between the 
Acari and Sarcoptes, or Itch-mite. On March 6th, Mr. C. 
Cooke called my attention to certain little mites (Pl. 6, fig. 
l) which were situated on the narrow groove between the 
main stem of the barb and the outer edge of the barbules 
of the feathers of the Downy Woodpecker, and subse- 
quently we found the other forms indicated in Plate 6, figs. 
2 and 3, in the down under the feathers. These long worm- 
like mites were evidently the young of the singular  Sarcop- 
tes-like mite, represented by figs. 2 and 3 of the plate, 3$ 
they were found on the same specimen of Woodpecker at 
_ about the same date, and it is known that the growth of 
mites is e. the opor occupying but a few days- 



