310 ME. R. I. POCOCK ON SCORPIONS 



The colour of the legs, palpi with the exception of the palely 

 inf uscate digits, and first three segments of the tail is a very clear 

 pale yellow ; the anterior six abdominal terga, with the exception 

 of their lateral portions, and usually the ante-ocular area of the 

 carapace are darker ; while the 4th and 5th segments of the tail 

 and the vesicle are a deep greenish black or brown. The dark 

 colour on the vesicle appears at a very early age, specimens 

 only 30 mm. long showing it very clearly ; whereas in the typical 

 liosoma the vesicle remains for a long while perfectly pale. 

 This is noticeable in specimens of about 70 mm. in length ; and 

 is well shown in Ehrenberg's figure of his type, which came from 

 Gumfuda in Arabia. P. Sunteri may be further recognized by 

 its much more slender tail. This difference, which at once strikes 

 the eye, may be easily shown by the following measurements, 

 taken from a S example of P. Zzosoma from Aden (/S'. i2. Shopland), 

 and a c? of P. Sunteri from Duroor, 60 miles north of Suakin. 

 These examples have the carapace of the same length, i. e. 10 mm. 



S liosoma. — Total length 95 mm., carapace 10, tail 60 ; length 

 of 1st segment 7-5, width 7-8 ; length of 2nd 8-8, width 8-3 ; 

 length of 3rd 9, width 8-6 ; length of 4th 10-5, width 8-8; length 

 of 5th 11, width 7. Width of brachium 3*4, of manus 4"5 ; length 

 of hand-back 6-2, of movable digit 9*3. 



S Fentonii. — Total length 100 mm., carapace 10, tail 66 ; 

 length of 1st segment 8'6, width 7*5 ; length and width of the 

 rest as follows : of 2nd 9-8. 7-8; of 3rd 10, 8 ; of 4th 11-3, 7-6; 

 of 5th 12-5, 7. Width of brachium 3*4, of manus 5 ; length of 

 hand-back 6"5, of movable digit 9'3. 



Corresponding diff"erences obtain in female examples; and 

 although subject to a certain amount of individual variation, 

 they appear nevertheless to be constant on the whole. 



A further distinction that may be noticed in the male is the pre- 

 sence in P. Hunteri of a tubercle lying at the base of each digit 

 of the chela ; that on the immovable one is of considerable size, 

 that on the movable is much smaller and closer behind the other. 

 These tubercles are not present upon any of the males of the 

 typical liosoma that I have seen, even upon the largest, and 

 presumably therefore the oldest. 



The largest male of Sunteri that I have seen is 113 mm. long. 



Log. Duroor, 60 miles N. of Suakin (36 specimens) ; Suakin 

 (2 specimens obtained by Surgeon- Captain Penton). 



I dedicate this species to Colonel Hunter, lately Governor of 

 the Eed Sea Littoral. 



