192 THE CArSES WHICH PROPAGATE 



ridge at the base of the abdomen^ which is rubbed against the 

 hard hinder part of the thorax. Regarding the crepitation of 

 the Mygale stridulans of Assam, Mr, S. E. Peal relates: " The 

 noise is both peculiar and loudj it resembles that made by 

 pouring out small shot on to a plate from a height of a few 

 inches, or, better still, by drawing the back of a knife along the 

 edge of a strong comb. The stridulation is very distinct, and 

 has a ring about it which I do not notice in the Orthoptera, 

 wherein it more closely resembles a whistling sound. It is now 

 some six years since I first heard it, and under the following 

 circumstances : Some Assamese were cutting out an old bamboo- 

 clump, the ground under which was dry and full of decayed 

 roots, and of holes. White ants had made a nest there, and I had 

 collected several ' queens.' While attending to these, with my 

 back to the clump, at a distance of some four or five feet, I 

 suddenly heard this peculiar noise, and turning, saw the man 

 who was hoeing the mound making futile blows with his hoe at 

 a huge black spider that kept up this curious sound ; but the 

 ground fortunately being uneven, none of the blows took effect, 

 and I soon secured the prize. On reaching the bungalow, I 

 undid the cloth in which it had hastily been secured beneath 

 an inverted tea-sieve. On stirring the cloth the spider ran out, 

 whereupon my cat pounced forward ; but the sj^ider, instead of 

 retreating, ran round and round inside its prison, following the 

 movements of the cat and stridulating louder than ever. When 

 thus roused the spider usually rested on the four posteiior legs, 

 raising the other four and shaking them in the air, with the 

 thorax thrown up almost at right angles to the abdomen, and 

 the chelicerae in rapid motion.''' The sound-producing apparatus 

 in this Mygale has been found to consist of a comb composed of 

 a number of highly elastic and indurated club-shaped chitineous 

 rods arranged close together comb-like on the inner face of the 

 basal joint of the palpi, and of a claftp, formed by an irregular 

 row of sharp erect spines on the outer surface of the penultimate 

 joint of the chelicerse, and equally well developed in the two sexes. 

 Two large scorpions allied to ^S*. afer, obtained by Mr. Wood 

 Mason from some Hindustani conjurors, when fixed face to face 

 on a light metal table, and goaded into fury, commenced to beat 

 the air with their palpi, and simultaneously to emit sounds 



