416 ZOOLOGY 
Scorpio, is also found in Mygale. Coxal glands are also pre- 
sent, in Mygale they seem to be closed, but in Atypus they 
open on both the first and third pairs of legs. 
Sub-order 2. DIPNEUMONES. 
This sub-order contains the majority of spiders, which are 
classified in very numerous families. petra diademata belongs 
to the EPEIRIDAE, a family the members of which make the well- 
known circular webs with radiating lines. Another family, 
the LycosmpAk, or wolf-spiders, includes the Lycosa tarantula of 
Italy and Spain. The THOMISIDAE, or crab-spiders, have a flat 
round abdomen and rather short legs; they frequently run side- 
ways, and build no webs. The AGELENIDAE make horizontal 
webs, prolonged at one point into a tunnel, in which the 
spider sits until some prey becomes entangled in the web, 
when it rushes out, kills it, and binds it up. This family 
includes the Agelena labyrinthica and Tegenaria derhamiu, the 
commonest household spider. Argyroneta aquatica, which also 
belongs to this family, makes a bell-shaped, water-tight nest, 
attached to some submerged water-plant. This it fills with 
air, carrying it down from the surface in bubbles which it has 
entangled between its spinnerets and the posterior pair of legs. 
Ciass VI. Phalangida. 
CHARACTERISTICS. — Arachnida with their abdomen not con- 
stricted off from the cephalothorax ; four pairs of very long 
and slender legs; they breathe by tracheae only ; chelicerae 
chelate. 
The Phalangida, sometimes called the Opilionina, and 
popularly known as harvestmen, resemble spiders in appear- 
ance, but have no constriction between the abdomen and thorax, 
and are almost always of a sombre gray, brown, or blackish 
hue. 
Appendages of Phalangium. 
1. Chelicerae. 4, 2nd pair of walking-legs. 
2. Pedipalpi. 5. 3rd 5 3 
3. 1st pair of walking-legs. 6. 4th ep p 
