Proceedings of the South African Philosoj^hical Society. vii 



produce in captivity a vibrating noise of comparatively short dura- 

 tion. The animal is usually resting on the ground with its huge 

 thighs folded against the body, which is not supported by the legs. 

 When alarmed, however, this huge body is suddenly raised upwards, 

 resting for a short time on the tarsi as if on stilts, while a shrill 

 rasping note is simultaneously produced by the abdomen being 

 rubbed against the supporting femora during its upward projection. 



The female of the large Stick-insect, Palophus haworthi, produces 

 when alarmed, a very loud, alarming noise by somewhat different 

 means from those of Methone. Her wings, which are folded over 

 the abdomen, are too short to support the body in flight, but when 

 alarmed, these fan-like, folded wings are suddenly opened with a 

 tearing sound, and the body is jerked upwards as in Methane.'^'- 



The females of Pneumorincv, belonging to the genera Pneumora 

 and Bulci, are wingless, yet they have rudiments of wings hidden 

 under the pronotum, which they use for producing a very loud rasp- 

 ing sound,! when threatened with seizure. The feeble creature 

 looks almost defiant when, danger threatening, she raises her 

 pronotum to produce the would-be terrifying noise, followed, how- 

 ever, by an attempt at getting rapidly away. She does not hop, but 

 walks, the result probably of the wonderful adaptation of her colour- 

 ing to her surroundings. 



Both sexes of the Carabidous beetle Microlestia tahida and M. 

 oxygona, the former fairly common on the slopes of Table Mountain, 

 stridulate with great force when alarmed or captured ; the noise is 

 produced by the rapid friction of the abdominal segments against the 

 wing-covers — the wdngs proper have disappeared. Most, if not all the 

 LamiincB of the Family CeramhycidcE, produce a somewhat similar 

 noise by moving the prothorax on the supporting part of the 

 mesothorax. Another beetle, Crioceris, does likewise. Trox stridu- 

 lates also w^hen captured. The Hymenopterous female Mutilla 

 does the same. 



Many more instances could I give you, but I think I have told you 

 enough to-night to show that Phoiiation in insects is not merely con- 

 nected with sexual purposes, but is also resorted to as protection 

 against possible foes. Of course we have no direct proof that a 

 natural enemy would be scared away from its prey by its intimi- 

 dating noise, but my own observations lead me to conclude that the 

 acquirement and the use made of these noise-producing organs, 

 either for courting or for defensive purposes, and probably for both 



* This noise and the attitude of the insect was sufficient to put to flight a tame 

 cat before which a female Haplolophus displayed her frightening tactics, 

 f Quite different from that of the male, and very much louder and shriller. 



