14 BRITISH BUTTERFLIES. 



that ill-favoured troop of darklings who have just 

 now issued from the lifeless shell. 



The truth is, that long since, perhaps in early larva- 

 hood, the creature's fate was sealed ; a deadly enemy to 

 his race is ever on the alert, winging about in the shape 

 of a small black fly, in search of an exposed and de- 

 fenceless caterpillar. Having selected her victim, she 

 pierces his body with a sharp cutting instrument she is 

 armed with, and in the wound deposits an egg; the 

 caterpillar winces a little at this treatment, but seems 

 to attach little importance to it. Meanwhile his enemy 

 repeats her thrusts till some thirty or forty eggs, germs 

 of the destroyers, are safely lodged in his body, and his 

 doom is certain beyond hope. The eggs quickly hatch 

 into grubs, who begin to gnaw away at the unhappy 

 creature's flesh, thus reducing him gradually, but by a 

 profound instinct keeping clear of all the vital organs, 

 as if knowing full well that the creature must keep on 

 feeding and digesting too, or their own supply would 

 speedily fail ; as usurers, while draining a client, keep 

 up his credit with the world as long as they can. 



Weaker grows the caterpillar as the gnawing worms 

 within grow stronger and nearer maturity. Sometimes 

 he dies a caterpillar, sometimes he has strength left to 

 take the chrysalis shape, but out of this he never comes 

 a butterfly the consuming grubs now finish vitals and 

 all, turn to pupae in his empty skin, and come out soon, 

 black flies like their parent. 



But, supposing that it has escaped this great danger, 

 we now see the creature in its completest form, as the 



IMAGO, OR PERFECT BUTTERFLY. 



The first term, Imago, is a Latin one, merely signify- 

 ing an image, or distinct unveiled form; as distin- 

 guished from the previous larva, or masked state, and 

 the pupa, or swathed and enveloped state. The word 

 imago then, in works on entomology, always means the 

 perfect and last stage of insect life, and is applied to all 

 insects with wings for it must be borne in mind that 



