266 MR. R. SHELFORD ON MIMETIC INSECTS AND [Nov. 4, 



represent very closely the whorls of a spirally coiled snail-shell, 

 such as Helix. 



The spider occurs in Kuching, and is generally found resting on 

 leaves, sometimes with the cephalothorax turned right under the 

 abdomen, in which position it is readily mistaken for a snail- 

 shell, or with the cephalothoi-ax in the normal position. In the 

 latter case, if disturbed, this part of the body is immediately 

 doubled under the abdomen and the animal usually rolls off the 

 leaf, especially if a small one, and becomes lost in the decaying 

 vegetation carpeting the gi'ound below. I have been unable to 

 discover any web, nor have I seen the manner in which the 

 animal hunts or seizes its prey, but it seems probable that this 

 is an example of one of those doubly significant devices whereby 

 an animal is enabled not only to avoid its foes (in this case pre- 

 datory wasps) but also to approach its own jjrey unobserved. 



[It is possible that this I'esemblance is ciyptic i-ather than 

 mimetic. The foinier intei'pi-etation seems to be valid in the 

 case of the British larva Asjnlates gllvaria, which also resembles a 

 snail-shell.— E. B. P.] 



ii. Mimic. Amycicea lineatipes (Pickard-Cambridge). 

 Model. Oiicopliylla smaragdina (Fab.). 



I am indebted to Mr. H. N. Ridley for leave to incorpoi-ate in 

 this paper the observations which he has made on this mimetic 

 species, which as yet I have failed to find in Borneo. The • ant 

 under notice is an extremely common and ferocious species, 

 chiefly remarkable for its nest-building habits. Mr. Ridley has 

 described these habits in the Journal of the Asiatic Society, 

 Straits Branch, 1890, No. 22, p. 345. The spider is of the same 

 colour as the ant (reddish brown), and bears on the posterior part 

 of the rather acutely pointed abdomen a pair of black eye-like 

 spots, so that it is the abdomen of the spider which corresponds 

 to the head, the cephalothorax to the abdomen of the ant. Both 

 mimic and model are found together near the nest of the latter, 

 and so close is the resemblance between the two that the spider 

 is able to prey with impunity on the ants : I have taken a speci- 

 men of a spider with the body of an ant sucked nearly diy in 

 its jaws ; and Mr. Ridley has seen an individual pounce on an ant 

 and then dropping from its foot-hold on a leaf, hang suspended 

 by a silk thread in order to complete its meal in safety. 

 No web is spun by the spider, but a round disc of silk, probably 

 the egg-cocoon of this species, was found on the under surface 

 of a leaf much frequented by the spider and its models. 



iii. Mimic. Salticus attenuatus (Pickard-Cambridge). 

 Model, An Ant. 



Mr. Ridley also sent me from Singapore a remarkable little 

 Attid with a well-marked constiiction about the middle of the 



