196 PLUM. 



In common \Yith other of the "Ambrosia Beetles," this 

 species is accompanied by a i^eculiar fungoid growth on the 

 "walls of its cells (see ante, p. 189) on which it feeds ; and in 

 relation to this point it may prove of practical interest to 

 mention that about the beginning of August in 1897 vast 

 numbers of a small black ok brown mite were found at Tod- 

 dington, by hundreds and thousands, crawling on the stems 

 of the Xt/lehonis-iniested trees. On submitting these little 

 mites (or A cart) to Mr. Albert D. Michael for certain identifi- 

 cation, he found them to be Orihata lapidaria, belonging to 

 the family of Orihatidce, which amongst other substances prey 

 on minute fungi, and therefore (it may be conjectured at least) 

 may help us in getting rid of the beetles by preying on their 

 special fungoid food. 



Methods of Prevention. — These are for the most part the 

 same which are applicable for lessening amount of X. dispar, 

 which have been mentioned in the preceding paper ; but it 

 has been suggested in reference to the habit of X. saxeseni of 

 making its way into apparently healthy wood through a dead 

 or dying patch on the bark, or a wound, that it might have a 

 good preservative effect if such places were treated by re- 

 moval of the dead bark, or paring the edges of the wound, 

 and painting the spots with kerosine emulsion (undiluted), 

 grafting-wax, or other dressings of a like character. 



Yet another method of action, which it is considered may 

 be effective in destroying infestation when in active life in the 

 tree, is to stop up the entrance-hole by running a piece of 

 wire into it. Thus it is said that the economy of the insects 

 is so disturbed that the beetles in their movements trample 

 down the fungus food, and thus all the contents of the cell 

 are destroj'ed together. 



The preceding notes of the habits of the two species of 

 Xylchoriis named are given, as far as la}^ in my power, from 

 English observations; but those who wish to study the most 

 recent observations in full detail will find excellently valuable 

 observations on different genera and species of the "Ambrosia 

 Beetles," with descriptions of different kinds of fungoid growth 

 accompanying their presence, and many illustrations, in the 

 paper by Mr. H. G. Hubbard, of which the title is given at 

 p. 193 ; and full information regarding X. xfjlograpJins = X. 

 saxeseni, including minute descriptions of the beetle in its 

 various stages, histor}^ habits, and means of prevention and 

 remedy, with two plates embodying about twenty-four figures, 

 will be found in the paper by Mr. A. D. Hopkins noted at 

 p. 193, thus bringing the record of observation up to February, 

 1898. 



