160 A NATURALIST IN BORNEO 



that are so useful to the Cicindela larvae as props, and 

 possibly as climbing-irons, would hamper the Collyris 

 larva, and so, in accordance with the rule that struc- 

 tures are adapted to requirements, we find these hooks, 

 though more numerous, much reduced in size. 



One interesting feature was seen in the piece of 

 stem bored by this Hong-Kong larva the part of the 

 stem occupied by the larva was swollen, an evident 

 pathological result of the injury inflicted by the larva; 

 I have seen similar swellings on plant stems tunnelled 

 by ants, and it is not unlikely that the huge bulbous 

 swellings on the roots of those remarkable plants 

 Myrmecodia and Hydnophytum, which afford perma- 

 nent shelters to colonies of ants, took their origin in 

 the first place from pathological swellings induced by 

 insects boring in normal tissues. 1 



Another very common Tiger-Beetle found, mostly in 

 old jungle, running about amongst the decaying vege- 

 tation, is Tricondyla gibba. Nothing unfortunately is 

 known of its life-history, which may be expected to 

 be different from that of Collyris and Cicindela. I am 

 inclined to suppose that the larva will eventually be 

 found burrowing in decaying wood ; but I must con- 

 fess that I have no facts to back my belief. 



A digression may now be made to consider very 

 briefly the adaptation of the fore-legs of many insects 

 for digging. These adaptations are strikingly apparent 

 when the fore-legs of certain burrowing insects are 

 compared with those of their non-burrowing allies. 



The fore-leg of the Mole-Cricket Gryllotalpa is fami- 

 liar to all entomologists, and it has been often figured 



1 There is no doubt that the swellings referred to precede the 

 insect attacks. H. N. R. 



