142 



INSECTS INJURIOUS TO THE PEAR. 



oblong-oval, pointed at both ends, and rather less than one- 

 twentieth of an inch in length. 



The larva is soft, yellowish white, of a cylindrical form, 

 rounded behind, witli a conical horny point on the upper 

 part of the hinder extremity, and when mature is about an 

 inch and a half long. It bores deeply into the interior of the 

 wood. Besides the pear, it is injurious to the buttonwood, 

 elm, and maple. 



From its secluded habits, this insect is a difficult one to 

 cope with ; fortunately, it is seldom present in sufficient num- 

 bers to be very injurious. It is said to be destroyed by 

 Ichneumon flies, species of Pimpla, furnished with very long 

 ovipositors, with which they bore into the trunks of trees 

 inhabited by these Tremex larvae, and deposit their eggs in 

 them : these hatch into grubs, which consume their substance 

 and cause their death. 



ATTAOKINa THE BKANOHES. 



Fig. 149. 



No. 67.— The Twig-girdler. 



Oncideres cingulatus (Say). 



This beetle nearly amputates pear twigs 

 during the latter half of August and the early 

 Q part of September. The female makes per- 

 ^ forations (Fig. 1 49, b) in the smaller branches 

 ..7 of the tree upon which she lives, and in these 

 !;. deposits her eggs, one of which is shown of the 

 natural size at e. She then proceeds to gnaw 

 a groove about one-tenth of an inch wide and 

 about a similar depth all around the branch, 

 as shown in the figure, when the exterior por- 

 tion dies, and the larva, when hatched, feeds 

 upon the dead wood. The girdled twigs sooner 

 or later fall to the ground, and in them the insect completes 



