71 



stage, with which I have never experimented. A serious injury to 

 the larva does not apparently cause it any great inconvenience. 

 An incision, or the removal of one of the claspers, causing much 

 bleeding, will be survived, and in the ensuing ecdysis will be com- 

 pletel}' healed ; an injury such as this will retard growth and cause 

 the subject to lag behind its fellows ; it will finally succeed in 

 pupating, but the cocoon will be a very poor structure, consisting of 

 a single layer of silk without the lining, which causes the opaque 

 finish so well known. An injury to the larva seems to cause an 

 absolute lack of the fluid which supplies this finish ; and the larva 

 may even pupate without attempting to make a cocoon. The imago 

 will duly emerge from an imperfect cocoon, but will be malformed ; 

 but in the case of a pupa that has had no cocoon, death is more 

 likely to ensue. This want of a cocoon seems to be more or less 

 fatal, for the removal of a perfectly healthy pupa from the cocoon 

 will often be followed by death, although it will stand extremely 

 rough treatment when in the cocoon. Death does not appear to be 

 caused by the absence of protection, but by the insect not being in 

 a position which enables it to emerge. 



The vitality of the imago is extraordinary. Cyanide of Potassium 

 is of very little use in killing the Zygaenas ; and crushing the thorax 

 is of no use at all. The poison they seem most susceptible to is 

 chloroform, which causes stupefaction in less than a second, and if 

 the moth is then put into a cyanide bottle death follows without 

 recovery. 



The only enemies of the Zygaenas seem to be Hymenopterous 

 parasite^, by which they are very frequently attacked ; but they 

 seem to enjoy absolute immunity from the attacks of birds. I have 

 collected Zygaenas abundantly on a ground that was overrun with 

 fowls. To test the matter I tried my own birds with the larvae of 

 trifnUi ; the first one or two put in the fowl run were greedily 

 attacked and killed, but on no occasion was one actually eaten ; 

 finally the fowls would not touch one. These birds had never seen 

 a Zygaenid larva previously. I then tried with fowls in a pen, which 

 had been running over the burnet ground alluded to previously, but 

 these birds would not even look at them, although a Lycaenid larva 

 thrown to them was instantly devoured. The objectionable feature 

 of the Zi/j/aena larvae seems to be small beads of an oily substance 

 which are exuded by the larva immediately it is touched, apparently 

 from several segments, but I have never been able to decide from 

 where this actually is exuded. I have tried on several occasions to 

 taste the fluid, but it is either tasteless or else the quantity is too 

 small to allow its appreciation. A similar oily fluid is present in 

 the imago in fairly large quantities, but instead of being colourless 

 it is orange, and when a freshly emerged specimen is pinned this 

 exudes freely from the wound, but the quantity decreases as the 

 insect gets older — a very old and worn insect will have little or none. 



