224 A NATURALIST IN BORNEO 



colour ; it is excessively abundant, and has a wide 

 distribution. It has the habit of flying into lighted 

 houses at night, and when it enters in numbers the 

 nuisance is considerable. I have seen a dinner-party 

 in confusion and the guests driven from the table by 

 an irruption of this noisome pest. Yet the bug does 

 not advertise its nauseous properties surely a very 

 singular fact. Again, most of the Coreid bugs are 

 cryptically coloured, and many of the species have 

 flattened leaf-like expansions on legs and thorax, char- 

 acters which we are accustomed to associate with 

 palatability and strictly cryptic habits. Yet these bugs 

 also have an extremely nauseating odour, and one asks 

 again why do they not advertise this ? The odour is 

 often so strong that one can detect the presence of 

 the bug before it is actually seen. Other Coreidce are 

 equally nauseous, and advertise themselves by bright 

 colours, e.g. Serinetha abdominalis, which is vermilion, 

 with the membranous parts of the elytra, the legs, and 

 antennae black ; it is furthermore mimicked in the 

 closest way by a moth, Phauda limbata, so that in a 

 state of repose it requires a sharp eye to say which is 

 which. Why then should some Coreidce be so con- 

 spicuous, others so inconspicuous, when all seem to be 

 equally nauseous ? These are puzzling questions, 

 which in the absence of experimental evidence I am 

 not prepared to solve. It may be that the unpalata- 

 bility is relative ; in fact, the cryptic species may 

 actually be palatable to some animals, although to our 

 nostrils all stink equally vilely. 



If the opponents of the mimetic theory regard 

 natural selection as quite inefficient to produce the 

 undoubted resemblances that do exist between insects 



