210 A NATURALIST IN BORNEO 



mimics most closely a large Tiger-Beetle, Tricondyla 

 cyanea, var. wallacei : the mimicry is so exact even in 

 dead and dried specimens that the famous entomologist 

 Professor J. O. Westwood found the first specimen of 

 this Locustid in a collection of Tiger-Beetles, while the 

 French entomologist Duponchel actually labelled 

 another specimen with the name of Tricondyla rufipes. 

 And yet what two insects could lead more different 

 lives ? The beetle hatches out from the egg as a small 

 grub, which probably lives in a hole in the ground ; 

 when full growth is attained the grub becomes a pupa, 

 and after a short resting stage emerges as the adult 

 beetle. The locust, on the other hand, hatches from 

 the egg to all intents and purposes a locust, recog- 

 nizable as such ; it hops about actively in search 

 of its food, and from time to time it casts its skin, 

 each moult marking a distinct increase of size until 

 finally the adult stage is reached. The young and 

 half-grown locusts do not mimic the adult Tricondyla, 

 they are too small to produce the effect of their model : 

 it is impossible for them to mimic the early stages of 

 the beetle, but the difficulty is obviated by their 

 mimicry of smaller species of beetles, the very young 

 locust resembling a small Collyris (C. sarawakensis), the 

 half-grown locust a small species of Tricondyla (T. gibba). 

 Now can anything more different than the life-histories 

 of these two insects be imagined ? Yet how close is 

 the mimicry. Evidently similarity of conditions has 

 not produced the likeness ; and scores of other cases, 

 though perhaps none quite so remarkable as this, could 

 be quoted, 



I have heard it stated by more than one field- 

 naturalist who has collected insects in the tropics that 



