268 Mr. R. I. Pocock on the Genera and 



notes upon the liabits of the species of Solpuga he has ob- 

 served. Many of these I take the liberty of quoting verbatim. 

 Mentioning in a letter that his attention had been attracted 

 to a specimen of a Natal species [probably 8. hostilis:'] by the 

 sound it produced when burrowing, he replied as follows to 

 a question of mine touching the stridulation of these 

 animals : — " Until tlie arrival of vour letter I had never 

 thought of attributing the sound to stridulation, but merely 

 to the trituration of the creature's powerful jaws against the 

 hard ground in which they seem to prefer to dig their holes, 

 the operation being performed with the jaws, and the sound 



ceasing when the spider stops digging When walking 



into Hartley the other day I captured an example of a small 

 species [probably S. sericea] which was running on the path 

 in the hot sunshine, apparently searching for insects. The 

 same evening I secured a specimen of yet another species 

 [probably S. Dar]in(]ii\ which came into my hut attracted 

 by the light. I kept them alive for a day or two, but failed 

 to detect any stridulating sounds whatever, though they both 

 made a considerable noise by energetically biting at the sides 

 of the boxes, one of them in a cardboard box nearly succeeding 

 in gnawing its way through at one spot. The evidence, so 

 far as it goes, only tends to increase my belief that the sounds 

 made by the Natal species were caused by trituration, not 

 stridulation. . . . But, unfortimately, owing to their lightning- 

 like activity it is impossible to keep these creatures in an open 

 vessel, and as the above specimens were both new to me, I 

 was afraid to experiment with them while free, for fear of 

 losing them." In a subsequent letter he adds: — "I was 

 interested to learn from you that the noise made by Solpuga 

 is really stridulation. I noticed the grooving on the mandible 

 in a very large nocturnal species which I came across on the 

 Umfuli River \8. Darliyigii\ but it never stridulated at all 

 while 1 was examining it before putting it into the cyanide 

 bottle. By the way, it is curious how much more rapidly 

 these creatures succumb to the effects of this poison than 

 either spiders or scorpions " *. And, lastly, writing in January 



* On the tenacity of life of scorpions Mrs. Monteiro (' Delagoa Bay: 

 its Natives and Natural History,' p. 192) makes the foUowint^ remark :— 

 " A large black scorpion was eight hours in my strongest poison-bottle 

 before it succumbed to the deadly fumes. When I touched him with a 

 stick after seven hours he elevated his wicked tail and opened his claws 

 wide in a most savage manner." The greater susceptibility of the Sol- 

 puga to the fumes as compared with the scorpion is doubtless connected 

 with the much richer development of its respiratory system, which 

 consists of an elaborate system of tracheal tubes, branching throughout 

 the body, that of the scorpion being composed of four pairs of small sacs. 



