SOLIFUO.K. 



133 



which ends in an apically pointed fang. The distal segment or 

 lower jaw, also toothed and terminating in a fang, is articulated 

 to the under side of the basal segment and moves in a vertical 

 plane, so as to constitute with the upper jaw a pair of powerful 

 nippers. On the inner side of the basal segment there is fre- 

 quently a series of hard ridges which, by being rubbed against the 

 corresponding ridges of the other jaw, give rise to a harsh grating 

 sound. These are the stridula ting- ridges. Projecting forwards 

 from the lower half of the fore part of the head between the 

 mandibles there is a horny, hair-tipped rostrum, which bears the 

 mouth at its extremity. The sternal elements of the cephalo- 

 thorax are practically absent, their place being taken by the basal 

 segments or coxae of the appendages, which meet each other in the 

 median ventral line and are immovably welded together. The 

 palpi are long, pediform, and consist of six segments, named 

 coxa, trochanter, femur, patella, tibia, and tarsus. The coxa is fur- 

 nished with a maxillary process ; the trochanter is very short ; the 

 tarsus, also short, is sometimes freely movable, but is generally 



B. 



C. 



Fig. 4G. — A, Palpus ; B, 1st leg ; and C, 3rd leg of Galeocle*. a, coxa ; b, tro- 

 chanter ; b' , trochantella ; c, femur of palp and trochantin of 1st and 

 3rd leg; c', distal end of femur of 1st and 3rd leg; d, patella; c, tibia; 

 f, tarsus; g, claws. 



united to the tibia, with a mere sutural line between the two. 

 The 1st leg much resembles the palpus, to which it is fused at the 

 base, but is shorter and weaker and has an additional small seg 

 ment, the trochantin, cut off from the base of the femur ; the tarsus 

 may or may not be furnished with a claw. The 2nd, 3rd, and 4th 

 legs are the organs of progression. They differ structurally from 

 those of the 1st pair in having the trochanters divided into two 

 distinct segments, so that between the coxa and the femur three 

 segments are intercalated, namely the trochanter, the trocliantella, 

 and troclia,<tin. This multiplication of basal segments confers ex- 

 ceptional flexibility upon the legs, and more than compensates tor 

 the rigidity of the COX8B. The patella and tibia are unsegmented : 

 the tarsi are segmented or not, and to the apex is articulated a 

 pair of long claws, which differ from those of all other Arachnids 

 in being pediculated or borne upon long stalks. Attached to the 



