322 Mr. G. A. K. Marshall on 



Plancnia cschria to D. All of theiu were eaten, though 

 D seemed a little suspicious at first, 



19. Gave Byhlia goctzius-achdoia to A, which ate it 

 readily, although she was a long time before coming down 

 to see what it was. 



20. Gave wingless specimens of A. liorta to spiders 

 A, B, C, and D (six days since last were given — Experi- 

 ment 16). Tlie first tliree promptly ejected them, but D 

 wrapped hers up and carried it off. She did not seem 

 very enthusiastic about it however, for she turned it over 

 and over a good many times, giving it a bite here and 

 there, and then left it alone for some time. This pro- 

 cedure she repeated several times, and then threw it away. 



21. Gave entire males of Acrma serena-huxtoni to 

 spiders A, C, and D, all of which were eaten. It should 

 be noted that experiments with this species are un- 

 satisfactory, owing to the fact that when captured it is able 

 voluntarily to exude from the thorax its bitter yellow 

 juice, and therefore when given to spiders it has lost much 

 of its nauseous quaHty, and w^ould be less distasteful 

 than if caught by them direct. 



5. Results of Experiments on Spiders and the 

 EARLIER Experiments on Mantid^ : One prob- 

 able meaning of tenacity of Life in distasteful 

 Insects. (G. A. K. M.) 



Malvern, Natal; Felruary 21, 1897. — The danger of 

 arguing from insufficient materials was clearly shown me 

 in my first few experiments on spiders with A. horta 

 (Experiments 1, 2, 3, and 6). When I had got thus far I 

 felt sure I had got proofs of the appreciation of warning 

 colours by the spiders. For in these experiments they ate 

 every specimen without wings and refused all those with 

 them except one which had the colour rubbed off. Yet 

 subsequent experiments have convinced me that both 

 spiders and Mantises have no appreciation of warning 

 colours ; and this fact has elucidated another which often 

 puzzled me, I mean the apparently constant correlation 

 between distastefulness and tenacity of life in Lepidoptera. 

 At first sight it would seem that tenacity of life or the 

 power to recover after severe injury would be useful to 

 any species in the struggle for existence. But a little 

 thought showed me that this power would be of no use to 

 edible species, as if once caught by insectivorous animals 



