NOTES FROM THE SARAWAK MUSEUM. 71 



they are at present known, mimics a tiger-beetle ; the models 

 are, it is true, of different species, but a moment's reflection will 

 shew that this is a necessity, for the young stages of an a meta- 

 bolic insect such as this locust cannot mimic the corresponding 

 stages (larva and pupa) of a holometabolic insect, such as the Tri- 

 condyla. which when adult serves as a model to the adult locust, 

 without undergoing a series of modifications of structure that 

 would completely alter the nature of the insect, — in short, the 

 locust would no longer be a locust. The difficulty is obviated by 

 the mimicking of different species of beetles, the model in each 

 case corresponding in size to the mimic. It would be a matter of 

 the greatest interest to discover the life histories of the Philippine 

 grasshoppers Scepastus pachyrhynchoides and Phoraspis sp. which 

 in their adult stages mimic respectively a weevil and a ladybird, 

 sa these might afford parallel examples to the life history of 

 Condylodera. 



On a Colour Variety of Coluber Oxycephalm (Boie). 



This well-known snake is usually brilliant blue-green in 

 colour, the tail alone being brown, but recently I obtained 

 amongst sandy scrub fringing high-water mark near the mouth 

 of the Trusan River an example with the head and body bright 

 ochreous and 4 the tail pale brown. Coloured in this manner the 

 snake was. considering its size, very inconspicuous against its 

 sandy background and it undoubtedly presented an example of 

 adaptation to the colour of its surroundings such as may be met 

 with in every desert area. The snake was preserved in formol and 

 when examined next day was still quite ochreous. Three days 

 later, however, the colour had reverted to the familiar blue- 

 green ; the preservative fluid was not discoloured so that the 

 change must have been brought about, not by a dissolving out of 

 pigment, but by some alteration of th* 1 shape or size of the pig- 

 ment cells or chromatophores. 



Mr. H. N. Ridley described in this Journal (Xo. 31, p. 89) 

 an interesting colour variety of another species of this genus. 

 Coluber toem 'urns (Cope), from the Selangor caves; this variety 

 was also protectively coloured but in adaptation to very differ- 

 ent surroundings from those of the C. oxycepkalus variety just 

 described. 



