58 MR. NEWPORT ON THE NATURAL HISTORY 



again on the mouth, and it again withdrew itself. By this time 

 it was evident that the snail was much injured, and I allowed the 

 larva to feed upon it. 



I then placed a healthy snail, No. 6, about the size of those just 

 noticed, and allowed this to be bitten once by a fresh and hitherto 

 unemployed larva. The wound in this was in the head : the snail 

 withdrew into its shell and never came forth again ; and two hours 

 afterwards I found that it was completely dead. This experiment 

 induced me to think, with my friend Professor Ellis, that the bite 

 of the glowworm is peculiarly poisonous to the snail, although I 

 was uncertain in what way it produces its effect. It was evident 

 from all the previous observations, that, even after the first bite 

 from a larva that had already expended its force on other snails, 

 the bitten snail writhes and seems to be in great agony ; and if a 

 young individual, it often dies from this single wound in a state of 

 contraction or kind of convulsion, giving out at the time a sanious 

 fluid. 



The circumstances noticed in these detailed experiments with 

 regard to the little effect produced on different snails by the same 

 larva which had previously bitten many successive times, and the 

 very marked result which instantly followed the bite of one which 

 had not before been employed, seem to support the opinion that a 

 fluid, which is poisonous to the snail, is injected into the wound 

 by the larva at the moment of its bite, and that the effect produced 

 is diminished in the ratio of the number of times the larva has 

 already bitten : precisely as in poisonous snakes, in which, as also 

 in the glowworm, we may suppose the want of power to produce 

 death may be due to exhaustion of the supply of their secreted 

 fluid, or to its imperfectly matured secretion and dilution with 

 other fluids. 



I may mention here, in support of the view that a poison is 

 injected, that I have noticed, on watching some larvae which were 

 preparing to attack the snail, a transparent fluid oozing from its 

 mouth and extended mandibles. Whether this fluid is secreted by 

 distinct poison-glands, as is the case with the centipede and with 

 serpents ; or whether it is merely a profuse flow of saliva, which 

 may act as a poison on the prey, is yet a subject for inquiry. 

 Certainly such a fluid is produced, and the mouth of the glowworm 

 is filled with it to overflowing at the moment of its attack. I have 

 witnessed the same thing in the Carabidce and in the Silphidce, 

 both of which generate an abundance of dark-coloured foetid fluid 

 from the mouth at the time they are feeding, though this I am 



