Fam. Sironidae.—These somewhat Mite-like Phalangids are rarely met with, partly, no doubt, because of their retiring habits and small size, the known forms ranging from 6 mm. to less than 2 mm. in length. Of the seven genera which have been established, Stylocellus numbers eight species from Borneo and Sumatra, and Pettalus two species from Ceylon. Ogovia, Miopsalis, and Purcellia have one species each, from South Africa, Further India, and the Cape, respectively. The only European forms are the two species of Siro (France and Austria), and Parasiro corsicus. No species has yet been found in England.
Sub-Order 2. Mecostethi.[[345]]
(LANIATORES).
Sternum long and narrow. Dorsal scutum leaving at least the last three segments free. Openings of odoriferous glands not on prominences. The fourth pair of legs usually long and powerful. One terminal claw on each of the first two pairs of legs; two on the last two pairs.
The Mecostethi are essentially tropical forms, though a few representatives are found in the caves of Southern Europe. One family (Phalangodidae) has its headquarters in the hot regions of the Old World, while the other two (Cosmetidae, Gonyleptidae) are confined to Central and South America.
Fam. 1. Phalangodidae.—Body piriform or triangular, broadest behind. Last ventral segment of abdomen much the largest. Very narrow sternum. Eye-turret near anterior border of cephalothorax. Chelicerae narrow at base. Pedipalpi long and strong. Maxillary plates on first pair of legs rudimentary. No stigmata visible.
The only European forms of this family belong to the genus Phalangodes. They all avoid the light, and are usually found in caves. Simon[[346]] records six species found in France. A North American species, P. armata, is entirely destitute of eyes.
Fig. [234].—Phalangodes terricola, enlarged. (After Simon.)
The family has representatives in Australia and in tropical Africa and Asia. Mermerus, Epidanus, Maracaudus, and Sitalces are some of the exotic genera.