22 INSECTS INJURIOUS TO FRUIT. 



If all the fruits were of the proper size at the same time, they might be placed 

 in the following order as to their liability to be attacked by the Curculio : Nectarine, 

 Plum, Apricot, Apple, Pear, Quince. Some varieties of the different kinds are pre- 

 ferred to others. The Green Gage, Washington, and Egg Plum will suffer more 

 than the Prunes, Damsons, and many of the common kinds. The earliest 

 Apples, as the Sweet Bough and Early Harvest, will be more injured than later 

 kinds. 



The black knot, so often found on Plum and Cherry trees, is used freely by the 

 Curculio. These knots are often several days in advance of the young fruit, and 

 the female Curculio has been known to exhaust her supply of eggs in these knots 

 before the young cherries or plums on the same trees were fully formed. 



Figure 2 shows the position of the Curculio when cutting the semicircle or 

 crescent-shaped mark. This is made by the end of the proboscis, and merely 

 goes through the skin. This part of the process, while the fruit is young and 

 tender, is soon finished, sometimes not taking more than two or three minutes. 



Fig. 3 shows her position in the next part of the work. From the centre of the 

 concave part of the crescent, the proboscis is introduced under this cut skin, and 

 there it slowly works, cutting its way until it can reach no further. 



The end of this cell or cavity is now dug out or enlarged, to make it a suitable 







receptacle for the destined egg. The insect has an instinct which teaches her that 

 the surroundings of this cavity must be so deadened that no subsequent growth of 

 the fruit at this part shall press upon that delicate egg and crush it. The seventeen- 

 year Locust arranges her eggs crosswise in cells made in the twigs of growing wood ; 

 but on one side of each cell the wood is so comminuted by the boring instrument 

 of the female Locust that it never recovers ; and although the twig generally conti- 

 nues to grow, this wounded part will not be grown over until long after the eggs 

 have hatched. Were it not for this instinctive foresight of the necessity of so splin- 

 tering up the wood on a side of the cavity where one end of these oblong eggs rests, 

 that it would yield to the pressure from the other, in the growth of two months, 

 these eggs must be broken. The Curculio probably has a similar instinctive fore- 

 sight. 



The preparation of this cell is much the most tedious part of the process, 

 usually taking about fifteen minutes, though sometimes half an hour. During most 



