| Fig. 64.—Liphistius desultor. Under side of the uplifted genital or first opisthosomatic somite of the female; g, genital aperture; p, pitted plate, probably a gland for the secretion of adhesive material for the eggs; l, the edges of the lamellae of the lung-books of the first pair. |
| (Original drawing by Pocock.) |
For an account of the courtship and dancing of spiders, of their webs and floating lines, the reader is referred to the works of M‛Cook (30) and the Peckhams (31), whilst an excellent account of the nests of trap-door spiders is given by Moggridge (32). References to systematic works will also be found at the end of this article (33).
Order 4. Palpigradi = Microthelyphonidae (see fig. 65).—Prosoma covered above by three plates, a larger representing the dorsal elements of the first four somites, and two smaller representing the dorsal elements of the 5th and 6th.
Its ventral surface provided with one prosternal, two mesosternal and one metasternal plate. Appendages of 1st pair consisting of three segments, completely chelate, without poison gland; of 2nd pair slender, leg-like, tipped with three claws, the basal segment without sterno-coxal process taking no share in mastication, and widely separated from its fellow of the opposite side; 3rd, 4th, 5th and 6th appendages similar in form to the 2nd and to each other.
Proboscis free, not supported from below by either the prosternum or the basal segments of the appendages of the 2nd pair.
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| Fig. 65.—Koenenia mirabilis, Grassi, one of the Palpigradi. | |
A, Ventral view of prosoma and anterior region of opisthosomawith the appendages cut off near the base; a and b,prosternites; c, mesosternite; and d, metasternite of theprosoma; f, ventral surface of the prae-genital somite;g, sternite of the genital somite (first opisthosomatic somite). | B, Dorsal view. I to VI, prosomatic appendages; 1 opisth,genital somite (first opisthosomatic somite). C, Lateral view, I to VI, prosomatic appendages; a, b, c,the three tergal plates of the prosoma; prae-gen, the prae-genitalsomite; 1 to 10, the ten somites of the opisthosoma. D, Chelicera. |
| (Original drawing by Pocock and Pickard-Cambridge, after Hansen and Sörensen.) | |
Opisthosoma consisting of only ten somites, which have no tergal and sternal elements, the prae-genital somite contracted to form a “waist,” as in the Pedipalpi; the last three narrowed to form a caudal support for the many-jointed flagelliform telson, as in the Urotricha. Respiratory organs atrophied.
Family—Koeneniidae (Koenenia).
Remarks.—An extremely remarkable minute form originally described by Grassi (34) from Sicily, and since further described by Hansen (35). Recently the genus has been found in Texas, U.S.A. Only one genus of the order is known.
Order 5. Solifugae = Mycetophorae (see figs. 66 to 69).—Dorsal area of prosoma covered with three distinct plates, two smaller representing the terga of the 5th and 6th somites, and a larger representing those of the anterior four somites, although the reduced terga of the 3rd and 4th are traceable behind the larger plate. The latter bears a pair of median eyes and obsolete lateral eyes on each side. Sternal elements of prosoma almost entirely absent, traces of a prosternum and metasternum alone remaining. Rostrum free, not supported by either the prosternum or the basal segments of the appendages. Appendages of 1st pair large, chelate, bisegmented, articulated to the sides of the head-shield; appendages of 2nd pair simple, pediform, with protrusible (? suctorial) organ, and no claws at the tip; their basal segments united in the middle line and furnished with sterno-coxal process. Remaining pairs of appendages with their basal segments immovably fixed to the sternal surface, similar in form, the posterior three pairs furnished with two claws supported on long stalks; the basal segments of the 6th pair bearing five pairs of tactile sensory organs or malleoli. The prae-genital somite is suppressed. Opisthosoma composed of ten somites. Respiratory organs tracheal, opening upon the ventral surface of the 2nd and 3rd, and sometimes also of the 4th somite of the opisthosoma. A supplementary pair of tracheae opening behind the basal segment of the 4th appendage of the prosoma.