The Hummino Bird. 47 



colour and shape they resemble the excrement of a bird, so 

 much so as to deceive even the most experienced eye ; 

 indeed, I should think that even the birds themselves were 

 mislead, so extraordinary is the similarity. They spend about 

 three weeks in the larval stage, and eleven or twelve days as 

 pupae. The Leaf Butterflies (Kallima) of India are brightly 

 coloured on the upper side of the wings, but quite sober 

 in hue underneath, and they look exactly likebrovvn leaves 

 when the wings are closed, the middle vein of the leaf being 

 represented bv a dark line extending across both wings, 

 which are also marked with blotches and spots, just like a 

 leaf commencing to decay. Each hind wing is elongated into 

 a kind of tail, which, when the butterfly is in repose, rests 

 against the stem of the plant on which the insect is sitting, 

 and thus resembles the stem of the leaf. They are very 

 variable in colour on the underside, all shades from vellow 

 to dark brown being found, and no two specimens are exactly 

 alike. One of the most difficult British pupae to And is that 

 of the Puss Moth (Dicranura vinula) , on account of the 

 shape and colour of the cocoon. When the larva is about 

 to undergo its metamorphosis it selects a comfortable crevice 

 in the bark of the poplar or willow tree on which it has been 

 feeding. It then bites the bark away in small chips until it 

 has made a sliorht hollow, a little longr-er and broader than 

 itself ; then, with the aid of a gummy secretion, which it 

 possesses in lieu of the silk with which most larvae of 

 Lepidoptera are provided, it proceeds to glue together the chips 

 of wood which it has bitten away, until it has built an oval 

 shaped dome over itself, which soon hardens with exposure 

 to the air, becoming almost impervious to the sharpest knife. 

 During; the winter months the cocoons oret discoloured, and 

 often covered with lichens, etc.. so as to be indistinguishable 

 from the bark of the tree. If comfined in a box, it will 

 compose its cocoon of cardboard or whatever substance the 

 box is made of. This larva is also interesting from the fact 

 that it has two so-called tails on the extremity of the body, 

 which are in realitv whips for drivino- awav ichneumon flies. 

 When it feels one of these flies alight on its back, for the 

 purpose of laying its eggs in the caterpillar's body, the larva 

 protudes these curious organs from the sheathes in which they 

 are encased, and uses them as whips to drive its foe away. 



Countless other examples could be added to those already 

 enumerated, such as the snail, which has a shell into which it 

 retires when threatened with danger ; the cuttle fish, which 



