90 Animal Life and Intelligence. 



As in the case of protective resemblance, so, too, in its 

 aggressive correlative, the resemblance may be general or 

 special, or may reach the climax of mimicry. And since 

 the same organism is not only a would-be captor, but 

 sometimes an unwilling prey, the same resemblance may 

 serve to protect it from its enemies and to enable it to 

 steal upon its prey. The mantis, for example, gains 

 doubly by its resemblance to the vegetation among which 

 it lives. Certain spiders, described by Mr. H. 0. Forbes, in 

 Java, closely resemble birds'-droppings. This may serve 

 to protect them from elimination by birds ; but it also 

 enables them to capture without difficulty unwary butter- 

 flies, which are often attracted by such excreta. A parasitic 

 fly (Volucetta bombylans) closely resembles (Fig. 20) a 

 bumble-bee (Bombus muscorum), and is thus enabled to enter 

 the nest of the bee without molestation. Its larvae feed 

 upon the larvse of the bee. The cuckoo bee Psithyrus 

 rupestris, an idle quean, who collects no pollen, and has 

 no pollen-baskets, steals into the nest of the bumble-bee 

 Bombas lapidarius, and lays her eggs there. The re- 

 semblance between the two is very great, and it not only 

 enables the mother bee to enter unmolested, but the 

 young bees, when they are hatched, to escape. Another 

 bee (Nomacla solidaginis), which plays the cuckoo on 

 Halictus cylindricus, does not resemble this bee, but is 

 wasp-like, and thus escapes molestation, not because it 

 escapes notice, but because it looks more dangerous than it 

 really is.* 



Many are the arts by which, in keen competition, 

 organisms steal a march upon their congeners — not, be it 

 remembered, through any conscious adaptation, but through 

 natural selection by elimination. Mr. Poulton describes 

 an Asiatic lizard (Plwynocephalus mystaceus) in which the 

 " general surface resembles the sand on which it is found, 

 while the fold of their skin at each angle of the mouth is 

 of a red colour, and is produced into a flower-like shape 



* I have to thank Mr. H. A. Francis for drawing my attention to this, 

 and showing; me the insects in his cabinet. 



