104 



THE OLIVE 



forming for each a niche which is enclosed by a partition made of 

 bits of wood agglutinated with saliva, and in twenty or thirty days, 

 from thirty to thirty-two eggs are deposited. 



Sometimes two females will enter at the same aperture and after 

 the first part of the gallery is completed will bore in opposite direc- 

 tions, often taking the form of a T (Fig. 1. e.) or a Y (Fig. 1. d.) 



The working of the insect is manifested by a small tumor or 

 windgall resembling soap foam which issues from the holes made by 

 them on entering. These excrescences are composed of excrement 

 and fibres of the wood mixed with salivarv fluid. The eeffs hatch 

 in fifteen days from the time they are deposited. The larvae 

 nourish themselves from the fibre of the wood boring secondary tun- 

 nels, the first perpendicular, with parallel ones between, resembling 

 much the reeds of an organ (Fig. 1. e.) 



The greatest length of a gallery or tunnel never exceeds three 

 quarters of an inch and is less than one-twelfth of an inch in 

 diameter. The number of the lateral tunnels are not usually more 

 than twenty on the same line or thirty on two lines. When the 

 female has finished depositing her eggs she crawls to the external 

 orifice of the gallery and dies. 



At the end of thirty or forty days the larva having reached the 

 maximum stage of development, bores into the bottom of its own 

 gallery, an oval niche (Fig. 1. e.) in which it remains immovable 

 and without food for eight or ten days. From this stage it passes 

 into that of the chrysalis casting its abdominal appendage. At the 

 end of another ten days (Fig. 10) the chrysalis becomes a perfect 

 insect which proceeds to gnaw the new wood of the tree, and the 

 bark about its cell, emerging according to the season, in April or 

 May. It flutters for a short time about the tree and then settles 

 down, and bores a hole at the fork of a bearing or blossoming 

 branch, which being deprived of its necessary nutriment soon 

 languishes and dies. In a few days the mating takes place and 

 about the first of June the boring of the tunnels for the depositing 



