STATB HORTICULTURAL SOCIETY. 



"3 



No other probable reason can be suggested than that they are aware 

 climatic conditions and the presence of parasites render these areas 

 unsuited for their offspring. 



Perhaps it will be said that insects in thus selecting appropriate 

 places for their young are led by instinct. But what is Instinct ? Who 

 can tell ? It is only a word coined to cover our ignorance ; a supposed 

 irresistible law of their nature of which we know really nothing. 



We see a little parasite approach our aphis, tap it with its antennae, 

 and, being satisfied, it punctures the body of the plant-louse with its 

 ovipositor, and deposits a tiny egg in its body. Another parasite 

 approaches the same plant-louse, and applying the same test leaves it 

 without depositing an egg. It is evident in this case that the aphis is 

 left undisturbed because another parasite had punctured it and deposited 

 an egg. Is the second aware that one grub only will find sufficient food 

 in the body of the aphis? The cabbage parasite, on the other hand, 

 deposits a number of eggs in the same pupa. Is the parent Ichneumon 

 in this case aware that her progeny will find sufficient food, or shall we 

 attempt to hide our ignorance by saying it is instinct? 



Let us now borrow some microscopic eyes and examine the eggs of 

 our cabbage-butterfly. If the light is sufficient they will appear like little 

 golden-green pears, fretted with delicate ribs and minute furrows, objects 

 of microscopic beauty (pointing to the illustration). 



But why is it that this species scatters the little glittering caskets 

 singly here and there, while the nearest of kin, Pieris brassicce, the 

 notorious white cabbage-butterfly of Europe, deposits a cluster of twenty 

 or thirty in a place? Science can give no other answer than that the 

 differences in this respect are specific laws. If we turn to Pieris oleracea, 

 the white cabbage-butterfly of this country, we shall find that it deposits 

 three or four eggs in a place ; while our native species, Pieris protodice 

 (referring to figure), on the other hand, deposits them singly. It is 

 probable that if we could trace the history of the species back to their 

 origin in the past we could learn the cause of this variation, but at 

 present this is one of the mysteries of insect life still closed to science. 

 So far man is unable to write the entire life-history of a single species of 

 the myriads of animals that inhabit the earth. 



As we gaze upon this little golden-green globule and strive to imagine 

 what it really is, thicker and thicker grows the cloud of mystery around 

 it. What is it? An embryo animal? Puncture it, and a little fluid is 

 all that is there. It is in fact a tiny bottle of life, sealed up, to be 

 developed at the proper time. How is it possible for the stream of life, 

 flowing down the race through the chain of individual links, thus to be 

 severed, and, as it were, bottled up ? An egg, which is but an enlarged 

 cell, is beyond all doubt one of the most wonderful productions of 

 Nature. How is blind force, if such life be, to plan the form, build it 

 up and give the peculiarities belonging to the species? Science has no 

 reply to make. And yet there are human wiseacres who, though unable 

 to explain this single process of Nature, will undertake to construct a 

 universe and operate it. 



