12 



appearance of the insect when expanded or when moving, be 

 expected or e\-en beh'eved possible, but which supplies that 

 fitness to its surroundings which seems to afford any Hving 

 creature the greatest security while in absolute repose. 



Taking first that most unpleasant phase of mimicry — that 

 to the excrement of birds — it is certain that no one who had 

 not closely observed them while at rest, would believe the 

 extraordinary resemblance, not only in the genera already 

 enumerated, but mPhtheochroa rugosana when sitting on a leaf 

 of Bryonia dzozca, Peronea variegana on a hawthorn leaf, or 

 EupcEcilia nana, perched on the extreme tip of a jagged 

 piece of birch bark, to the party-coloured droppings of various 

 species of small birds. Cilix spiiiula, with its wings shut 

 closely together clasping the body, may readily be passed over 

 for similar material, and so may Acidalia rusticata when 

 closely appressed to an elm leaf at the bottom of a hedge, 

 and the likeness of a pair of Leiocampa dictceoides , with their 

 well-clothed legs extended on the low expanded portion of a 

 birch trunk, to the smooth dropping of a large bird, must be 

 seen — as I have seen it— to be comprehended. But we may 

 go even further than this. In open woods the trees are often 

 tenanted by numerous ringdoves {Coluniba pabimbus), and the 

 brambles, dogs-mercury, and other plants growing underneath, 

 have their leaves plentifully splashed with the white fluid 

 ejected by the young birds. In the more northern woods, 

 Abraxas ulmata sits upon the leaves in the same places, and 

 the manner in which its white colour and clouded grey and 

 brown spots harmonize with the splashes in question, is 

 wonderful. 



The trunks of oak trees in woods are plentifully ornamented 

 with tufts of lichen, divided into innumerable branchlets ; or 

 with patches of other lichens, white or grey, generally much 

 mixed with moss. Here Chariptera aprilina is hardly dis- 

 tinguishable from a tuft of lichen, even Liparis monacha may 

 readily be passed over in the same way, and it is actually im- 

 practicable to see Leptograimna literana and Sarrothripa 

 revayana. They become visible when blown off. Psoricoptcra 

 gibbosella is equally invisible when the oak trunk is fairly clear 

 of lichen, its raised scales and peculiar arrangement of colour 

 harmonize precisely with the bark ; and it is most amusing 

 when scrutinizing an elm trunk, to see a GelecJiia fiigitivella 

 suddenly move from a chink in which it had been quite un- 

 distinguishable, run to another, and disappear. Nola confiisalis 

 sits head downwards on a projecting piece of bark, and seems 

 to be a bit of white lichen ; and Erastria fiiscula nestling 



