402 Dr. Sharp s account of recent e.vperiments 



by means of its antenna, but walks in a stupid manner 

 against black obstacles, which Plateau says it probably 

 takes for dark cavities where it may conceal itself. 

 When, instead of placing a comparatively large obstacle 

 in the way of the insect. Plateau made use of some 

 small object, such as a pencil or the handle of a knife, 

 so that the antennEe did not come into contact with it, 

 but projected on each side of it, then the insect invariably 

 knocked against the obstacle. 



Similar results were obtained with Forjicula auricu- 

 laria : the insect apparently did not at all perceive black 

 obstacles, or such as were of a neutral colour, but it did 

 perceive at a distance of 5 — 10 centimetres (2 — 4 in.) an 

 obstacle of white colour fully illuminated, and turned to 

 one side sufficiently to avoid it. 



Locusta viridissima , when placed in the middle of the 

 maze, walked straight up to the first obstacle, explored 

 it with its antennae, then climbed on it, but when on it 

 did not perceive even the ground on the other side, but 

 likewise ascertained the existence even of this by the 

 aid of its antennae. 



Carahus monilis was then tried ; it walked against the 

 objects, and then used its antennae to explore them, 

 then circumvented the object, and proceeded in a similar 

 manner with the next obstacle, following, however, some 

 particular direction. When the eyes were obscured 

 with black pigment, though it acted in a similar manner 

 with its antennae, it did not follow any general direction, 

 but wandered about at random. Carahus nemoralis 

 acted in a similar manner, there being, however, this 

 difference, that in the latter the general direction of its 

 movements is towards the light, while in C. monilis it is 

 away from the light. Carahus auratus was apparently 

 even more stupid. And similar results were obtained 

 with other Carahidce. 



Cicindela cainpestris was then tried : this insect is 

 very active, and in order to prevent it using its wings 

 these were clipped ; it then ran with great rapidity. 

 Another specimen that was not fond of flying was used 

 without any mutilation : both gave similar results. The 

 chief difference from Carahidce was found to be that the 

 Cicindela evidently distinguished the streaks of light 

 that passed through the gaps between the obstacles, but 

 there was no indication of the species perceiving the 



