ORDER PULMONARLE. 
429 
trapezium. There are four in front on a transverse line ; two 
others, more interior than the two preceding extreme ones, 
compose a second transverse line ; the last two are behind the 
two preceding ; the forceps are strong; the jaws are rounded, 
and very hairy at the end ; the tongue is almost square, a little 
longer than broad ; the feet are long, almost filiform ; those of 
the fourth, and the first pair, are the longest of all ; the thorax 
seems divided into three parts, the anterior of which, much 
larger, is square, and the other two in the form of knots or 
bosses ; the abdomen is much shorter than the thorax, and 
covered from its origin to its middle with a solid epidermis. 
Myrmecia fiilva, on which I have established this genus, 
is found in Brazil. But it appears that other species of it 
exist in American Georgia. 
The second section of Erratic Spiders, that of Salti- 
GRADES, has the eyes disposed in a large quadrilateral figure, 
the anterior side of which, or the line formed by the first, 
extends through the whole breadth of the corslet ; this part of 
the body is almost square, or semi-ovoid, plane, or but little 
gibbous above, as broad in front as in the rest of its extent, 
and falls abruptly on the sides ; the feet are proper both for 
running and leaping. 
The thighs of the two fore-feet are generally remarkable for 
their size. 
The spider a chevrons hlancs of Geoffroy, a species of 
Salticus, very common in summer on walls or glass-windows 
exposed to the sun, walks as it were by jerks, stops short after 
having made a few steps, and raises itself on the anterior feet. 
If it discovers a fly, or a gnat more especially, it approaches 
quite softly within a distance which it can clear at a jump, and 
then instantly darts on the animal which it was watching. It 
does not hesitate to leap perpendicularly from a wall, in con- 
sequence of the thread of silk which attaches it, and which it 
unwinds in proportion as it advances. This also serves to 
