HAIRY CATERPILLARS 213 



at any rate in the case of Lepidoptera. It is quite impos- 

 sible to kill a Danaine or Acraeine butterfly by the mild 

 pinch on the thorax sufficient for a non-aposematic Pierine 

 or Satyrine, for their tissues are so elastic that but little 

 impression is made on them. Further, such insects have 

 remarkable powers of resistance to chemical poisons.^ 

 It takes a very long time to kill an Acraea, or a Burnet 

 moth, in a cyanide bottle, and I have had Planema pupae 

 all night in a killing bottle, which when taken out in the 

 morning were unharmed, and showed their characteristic 

 movements, although that very bottle was in daily use 

 for other insects, which very quickly succumbed. 



It has been pointed out above that a disagreeable taste 

 or smell is not the only quality associated with aposemes, 

 as in the case of the sting of a wasp. The well known 

 irritating qualities of fine hairs from Arctiid, Lymantrid, 

 or Lasiocampid caterpillars, or the spines of Apodid or 

 Saturnid caterpillars are all found to be associated with 

 typically aposematic colouration. In this case the aposeme 

 has no bearing on the actual taste of the insect, but only 

 refers to the presence of some irritant or penetrating 

 hairs ; indeed, many such caterpillars, as in Lymantridae, 

 become typically procryptic, and presumably edible moths. 

 But the rule cannot be stated that when the aposeme is 

 due to adventitious hairs, etc., the insect is not distasteful 

 in itself, for many Arctiid caterpillars renowned for their 

 hairiness, such as the " Woolly Bear," become typically 

 aposematic moths, such as our English " Tiger-moth." 

 It would, however, be very interesting to test the edibility 

 of Lymantrid and Arctiid pupae removed from the hairy 

 cocoon. On the other hand, when a caterpillar has 

 aposemes that are, as it were, intrinsic, that is, not de- 

 pending upon hairs or spines, it seems to be the rule hat 



^ It must be acknowledged, however, that certain very procryptic 

 weevils, found on the ground which they closely resemble, have equal 

 powers of resistance to chemical poisons, but they are exceptional in 

 this respect among procryptic species. 



