SPIDERS 
GREAT BRITAIN AND IRELAND. 
Class ARACHNIDA. Order ARANEIDEA. 
Tribe 0 CTONOGULINA. 
Family MYGALID/E. 
The Mygalida , which abound most in hot climates and comprise the largest spiders known, 
have the falces articulated horizontally; two branchial and two tracheal opercula, situated near 
the anterior extremity of the abdomen, on its underside, are conspicuous in most species, but 
in some the branchial opercula only are apparent; much the greater number are provided with 
two pairs of spinners, and have the inferior surface of their biungulate tarsi, and of the digital 
joint of their pediform palpi, in the females, densely clothed with compound, hair-like papillae, 
constituting an apparatus which, by the emission of a viscous secretion, enables them to 
traverse the perpendicular surfaces of dry, highly polished bodies; others have three pairs of 
spinners, are destitute of hair-like papillae on the legs and palpi, and have the tarsi terminated 
by three claws. 
The spiders belonging to this extensive family conceal themselves in holes in the earth, 
in hollow trees, or among the leaves of plants, and prey upon large insects, which they 
actively pursue or take by surprise; hitherto, only one species has been found in Great 
Britain. 
