320 Insects and their Surroundings 



shadow among green foliage. Yet probably on 

 account of their large size rendering them too con- 

 spicuous many of these caterpillars feed only at 

 night, hiding by day on the ground. Several species 

 which have adopted this habit are brown after the 

 last moult instead of green, in correspondence with 

 their resting-place ; though the occurrence of an 

 occasional full-grown green specimen shows that the 

 habit has not been very long acquired. A vast 

 number of caterpillars, however, belonging to various 

 families feed always during the night. The value of 

 protective resemblance is greatly lessened by move- 

 ment, and it is therefore of advantage to these insects 

 to be able to remain at rest throughout the hours 

 of daylight (83 a). 



Warning Colour. — But it is a matter of common 

 observation that many insects are not coloured so as 

 to be hidden, but rather so as to be as conspicuous as 

 possible. The black and yellow banding of Wasps 

 and many Bees, and the red, black-spotted Ladybird 

 beetles ; the red and black pattern of the Burnet and 

 Cinnabar moths, and the yellow and black segmentation 

 of the latter's caterpillar, are familiar examples of this 

 fact among British insects, while abroad it is found 

 that entire groups of Butterflies — the Heliconiinae, 

 the Danainae and the Acrseinae — are marked by a 

 glaring livery of some combination of brown, red or 

 yellow with black or white, the pattern of the upper 

 surface of the wings being substantially reproduced 

 beneath, so that the insects are as conspicuous when 

 at rest as when flying. Such bright colours are 

 usually explained as of "warning" significance. They 

 are believed to be associated with some noxious or 

 hurtful quality whereof they act as an advertisement, 

 insects possessing them being at once recognised as 

 nasty or dangerous and therefore let alone by would- 



