A cari. 
Fam. — Bdcllidae. 
The members of this 
family are soft-skinned 
mites, with a distinct 
rostrum. The first pair of 
appendages are in the form 
of pincers and the palps 
are slender and unarmed. 
These mites are free- 
living terrestrial forms, 
which lead a predatory 
life. There are a number 
of British species. A 
little red species (. Bdella 
littoralis) is common on 
our sea-coasts. 
SUB-OEDEE Y. 
ASTIGMATA. 
In these Acari, which 
are closely allied to the Prostigviata, there is no trace of a 
respiratory system. 
Many of them are parasitic, others are free-living and feed on 
animal and vegetable refuse. 
It is to this sub -order that the 
mite ( Sarcoptes scabiei) which 
is the cause of itch belongs. 
The cheese mite ( Tyroglyphus 
siro) is perhaps the most fami- 
liar of the non-parasitic forms. 
Another species ( Glycyphagus 
domesticus ) is often found in 
houses. Drawings of these two 
species are shown in Table- 
case 26. 
A tuft of wool, with some of 
the flesh still attached, showing 
the scab caused by a Sarcoptid 
mite ( Psoroptes communis , var. 
ovis), together with drawings 
of the mite itself, is on view 
in the North Hall. 
i 
| 
House-mite, Glycyphagus domesticus , 
X 50 (after Michael). 
Table-case 
No. 26. 
Fig. 74. 
Sarcoptes scabiei , the itch mite, x 100 
(after Canestrini). 
