Savory - Arachnida 1977

194 III. PROLES ARACIINES
25. THE ORDER CYPHOPHTHALMI 195
FIG. 74. Larva of Siro. After Juberthie.
A cyphophthalmid can protect itself from aggressors by the use of its
malodorous secretion. Threat causes the appearance of a little liquid
at the orifice of the duct, one of the legs is made to touch this, and the
drop deposited on the aggressor. This direct method of bringing the
repellant to the foe is peculiar to the order.
FIG. 73. Cyphophthalmi: (i) penis and (ii) ovipostor. Mter Juberthie.
consists of about 30 rings and ends in a pair of long lobes, the whole
reminiscent of the ovipositor in the Phalangodidae.
Most probably it is used in the same way. In groups of three to five,
eggs are laid in in the soil at intervals from spring to autumn:
they are small green spheres, less than half a millimetre in diameter.
w-ithin a week a larva is hatched; it cannot feed, but lives on the yolk in
its gut until, hiding itself in some safe spot, it moults. Figure 74 shows
how different is this larva from any early stage of any other arachnid,
including even the Opiliones. Ecdysis changes the larva into a nymph,
resembling the adult, save in size. Its behaviour between one ecdysis
and the next is characteristic. For seven or eight months it lives a
normal life in the cryptosphere; it then digs a hole into which it shuts
itself with the loosened soil. Here it remains for four months or so, until
it emerges a large nymph, a year older than the nymph that dug the
hole. Four years may be occupied in this remarkably slow development
before a fourth ecdysis produces an adult. Adult life may last for five
years, giving a total life span of nine years, a period of time scarcely
approached by any other small arachnid.
The food taken during this time seems to consist of Collembola and
Protura, animals that supply the usual diet of most of the Cryptozoa.
DISTRIBUTION
The first species of the order, Siro rubens, was discovered by Latreille at
Brive in the south of France in 1796, and it is from France that much of
our recent knowledge of these Arachnida has come, and which we owe
to the work of C. Juberthie. The order is widespread in the tropical
and temperate zones, where a proportion of the species are found only
in caves. As the map (Fig. 75) shows, their occurrence, as so far known,
is discontinuous, a feature characteristic of many primitive animals.
Their range stretches from Oregon to New Zealand, from Chile to
Japan.
CLASSIFICATION
Two families have been distinguished, Sironidae and Stylocellidae. The
former includes some 15 genera, the latter about ten. The typical genus,
is also the best known, the genus Rakaia, with 20 species, mostly from
New Zealand, and the largest. The chief difference between the families
is the existence of eyes in the Styllocellidae while the Sironidae are blind.
The removal of the Cyphophthalmi from the Opiliones, with the
consequent establishing of a new order, was not undertaken without
considerable thought and correspondence with other arachnologists
(Savory, in press).