112 THE CANADIAN ENTOMOLOGIST. 



thougli the act is iuslinciive and inv(;lves neither practise nor imitation, it 

 is not absolutely perfect ; leaves have been found cut in more than one 

 place and then abandoned as unsatisfactory. 



There is a very interesting account of a British leaf-roller (Rhynchites 

 betulce) given by Sliarpe in the Cambridge Natural History. The female 

 beetle goes to the margin of the leaf, at the base, but some way out from 

 the stalk, and cuts through the leaf from the margin to the mid-rib some- 

 what in the shape of an upright letter S \ it then crosses the mid-rib and 

 cuts through the other half of the leaf to the margin, somewhat in the shape 

 of a prostrate letter S. The beetle then returns to the margin, where it 

 begins cu'ting, and, much as a grocer m^kes a paper funnel for sugar, rolls 

 the edge over round an ideal axis till it brings it to the midrib ; here it 

 holds the funnel in position with the legs of one side, \vhile with the other 

 three it draws the further side of the leaf towards it and wraps it around 

 the part of the funnel already formed. When it finds the material stiff to 

 work with, it bites the surface of the leaf with its mandibles or pushes it 

 into position with its feet, adjusting means to end like a sailor at work in 

 the shrouds furling canvas. It then enters the funnel, bites two or three 

 small pits into the leaf, deposits an egg in each, and, then emerging, com- 

 pletes the funnel by folding over and tucking in the tip of the leaf. 



Mr. Sharpe, in comment, points out that the insect has never seen a 

 funnel in its life, and yet manages to make one perfectly the very first time 

 of trying. But the author's perplexity is partly due to his confusing a 

 purely instinctive act with an act of intelligence (vide the Beckham's book 

 on Wasps). How can an insect be a highly-skilled engineer, working 

 with mathematical accuracy and on a scientific plan ? It is an insoluble 

 problem if you try to state your answer in terms of intelligence and indi- 

 vidual consciousness. But place it among impulsive acts, involuntary and 

 more or less mechanical, common to all members of the. species, and you 

 can give a fairly satisfactory explanation in terms of instinct. 



Among insects especially are found instincts whose perfection is 

 simply diabolical, often involving a highly-complex series of acts performed 

 but once in the whole lifetime of the individual, and therefore admitting 

 of neither practise nor imitation. To look upon such acts as the result of 

 conscious intelligence is absurd ; the intellect has no place here, and would 

 be simply a meddler, likely to bungle and make a botch of the artificer's 

 work. On the other hand, a whole-hearted Darwinim like Weiomaur has 

 no difficulty in applying his great principle of selection to such an act, and 



