GLOW-WORMS, TERMITES, SHELLS 210 



progression, since by means of them the glow-worm 

 can obtain a very firm hold. The insects also use 

 these suckers for the purpose of cleaning their bodies. 

 They feed on snails, and the mucus of the prey often 

 smothers their bodies in slime. The glow-worms 

 remove this by flexing their bodies and turning for- 

 ward the tip of the abdomen so as to be able to brush 

 away the mucus with their tuft of suckers. 



The large females shine with a very brilliant light. 

 On the under surface of the eighth abdominal segment 

 are two smooth white patches, oval in shape, one on 

 either side of the segment. At night these patches 

 emit a beautiful green light, of a penetrating nature, 

 and resembling in colour the brilliant phosphorescence 

 of the ocean. The light is fixed and steady ; it does 

 not pulsate in the same rhythmical manner as in the 

 firefly. The glow-worm shows a continuous gleam : 

 the firefly is a twinkling star. Owing to the luminous 

 patches being directed downwards, the lights are largely 

 hidden from above. The portion of the ground on 

 which the rays fall is a transverse patch, since the 

 light spreads out on either side of the abdomen. One 

 large female illuminated an area of newspaper one inch 

 in length with sufficient intensity to enable me to read 

 the print. None of the rays extend to the head of 

 the insect, so that the light can be of no assistance 

 in the findinor of food. Nor can it be thoui^ht that 

 a light, so concealed beneath the abdomen that most 

 of its rays are hidden, could be of much use for one 

 insect to attract another. I do not think a glow-worm 

 is capable even of perceiving a light. At all events, 

 one, which I kept apart for twenty-four hours, did not 

 seem to take any notice of a brilliantly glowing female 



