Insects, etc., Injurious to the Plum. 371 



maple, poplar, and various conifers. The only record I know of it 

 causing any harm in fruit is one given by Ormerod (1), who mentions 

 it from Toddington, Gloucestershire, in 1889. 



LlFE-HlSTOEY AND HABITS. 



The female is rather more than ^ inch in length, the male some- 

 what smaller, but broader. In colour they are almost black, with 

 some grey hairs ; the males are wingless and paler, almost brown. It 

 differs from X. dispar in not having the thorax raised in the middle 

 into a hump. The beetles (female) pass the winter in the brood 

 chambers and emerge in the spring. They then enter trees by the 

 edge of a wound, or at a dead part of a tree and excavate their brood 

 chamber. This chamber is enlarged by the lame, which are white, 

 and very similar to those of the former species, and about -j^ inch 

 long ; here they mature and pupate. This chamber is formed at the 

 end of a gallery, which may penetrate into the heart of the tree 

 or remain in the sapwood, according to Hubbard (2). 



The larvte are described as passing out the wood pulp as a 

 mustard-coloured mass, and great quantities are ejected from the 

 opening of the colony, but some remains and is plastered on the 

 walls of the chamber to serve as soil for a new crop of the 

 " Ambrosia " fungus used for food by the maggots. 



The larvte are found in England in July, when some appear to 

 pupate. These larva? and pupa? are tightly packed in the chambers, 

 which may reach nearly 1 inch in length, and according to 

 Ormerod (1) are covered for the most part with a very thin coating 

 of a wax-like material, greyish in colour and with a somewhat sweet 

 scent, " and the surface of the wood of the chamber, wherever it was 

 visible, was certainly not of the black colour so noticeable in con- 

 nection with the workings of X. dispar. It was rather of a brown 

 colour and moist-looking appearance." 



I have never seen this attack, which appears to be uncommon in 

 this country. 



Ormerod (1) mentions that numbers of Beetle Mites (Oribata 

 lapidaria) were found on the infested trees, and suggests that they 

 might be feeding on the " Ambrosia " fungus. 



PREVENTION. 



Very similar steps may be taken as for X. dispar to keep this pest 

 down. One point we may bear in mind and that is, that the beetles 



2 B 2 



