Savory - Arachnida 1977

160
Ill. PROLES ARACHNES
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18. THE ORDER ARANEAE 161
perfectly concealed silk tubes on tree trunks. The Theraphosidae are
the "bird-eating spiders", the typical hunters of the sub-order, and
include the largest known species in the genera Theraphosa from New
Guinea, Eurypelma and Avicularia from America.
The Labidognatha include the bulk of the world's spiders from all
regions .
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FIG. 58. Map showing distribution of Thcraphosomorphae.
FIG. 57. Map showing distribution of Liphistiidae.
"tarantulas" of America. They are generally large spiders, with a
squarish prosoma and eyes on a small ocular prominence. Their
chelicerae, like those of the Liphistiidae, are articulated so that they
strike vertically downwards, piercing their prey in parallel directions
from above. The proximal segment is in many genera provided with a
rake or rastellus used in excavating the burrow. The pedipalpi are long
and leg-like and there are two pairs of book-lungs. In most genera there
are four spinnerets. The sub-order includes wandering species, which
hunt their prey, others which dig holes in the earth and close them with
trap-doors, and others which spin silk tubes above the ground or make
a web similar to that of Agelenidae.
The family Atypidac, which includes the British Atypus affinis, is the
only one found in temperate regions. The Paratropididae from the
Amazon and Pycnothelidae from Brazil arc also small families. The
rest are of wider range. The ~1igidae are found in South Africa,
Madagascar and ~ew Zealand. They do not burrow, but make
Among the cribellate forms, the Hypochilidae are most interesting.
There are two species, Hypochilus thorelli from ~ orth Carolina and
Tennessee, and Ectatosticta dauidi from China. Their systematic position
is doubtful, for they possess two pairs of book-lungs, a characteristic of
the Theraphosomorphae, but in no other way are related to this suborder.
They have six spinnerets, and in many ways show primitive
features. Some systematists have put them in a sub-order of their own.
The Amaurobiidae and Dictynidae are the most widespread representatives
in temperate regions. The Eresidae have a quadrangular
prosoma, very similar in shape to that of the Salticidae, and the Uloboridae
are of great interest since they spin orb-webs.
The Apneumonatae include three somewhat aberrant families, Telemidae,
Caponiidae and Symphytognathidae. The Telemidae are small,
cavernicolous spiders. The genus Telema includes the blind species T.
tenella from the Pyrenees; the other genus, Apneumonella, has eyes and
lives in East Africa.
The Caponiidae-include barely a dozen species. The genus Caponia