80 PLUM. 
observable in the specimens sent me from Toddington of the Xyleborus 
vylographus, Say = saxeseni, Ratz. :— 
‘The young in this species are assembled ina brood chamber. . . . 
It is constructed at the end of a gallery which penetrates deeply into 
the heart, or remains in the sapwood, according to the amount of 
moisture in the tree-trunk, . . . and stands vertically on edge parallel 
with the grain of the wood. The space between the walls is not much 
greater than the thickness of the bodies of the adult beetles.” [See 
my own observations preceding on the narrowness of the chamber from 
side to side, and also as to the larve working away the wood, p. 78.— 
K. A. O.] “The larve aid in extending the brood chamber. They 
swallow the wood which they remove with their jaws, and in passing 
through their bodies it becomes stained a mustard yellow colour. 
Great quantities of this excrement are ejected from the openings of 
the colony, but a portion is retained, and plastered upon the walls, 
where it serves as a bed upon which there springs up a new crop of 
the food fungus.” 
The nature of this fungus is of great interest, and has been the 
subject of much discussion from the time of Canon Schmidberger, who 
described this substance (of which the nature was not then known) 
under the fanciful name of ambrosia,* up to the elaborate observations 
given, with illustrations accompanying, by Mr. H. G. Hubbard in his 
paper on the ‘‘ Ambrosia Beetles,’’ lately published, and referred to in 
note at preceding page. 
At p. 9 Mr. Hubbard states that ‘the term Ambrosia Beetles is 
used as a convenient one to distinguish from the true bark-borers and 
bark-eaters’ [the Elm-bark Beetle, Scolytus destructor, for example,— 
K. A. O.] “the timber-boring Scolytide, which push their galleries 
deeply into the wood, and which feed upon a substance called am- 
brosia. . . . Their food consists not of wood, but of certain minute 
and juicy fungi propagated on the walls of their galleries.” These 
fungi, it is stated, are of different kinds, each species of ‘* Ambrosia 
Beetles” (or, if not strictly each species, only those most closely allied) 
feeding on one kind, and one only of ambrosia fungus. Some of these 
fungi are like a pile of beads in appearance, but the Xyleborus saxeseni 
(= wylographus) fangus is of upright stems set close together, with a 
swollen cell at the end of each, and not unlike in general appearance, 
when enormously magnified, to a great number of short, very thick- 
stemmed pins, with round heads, set very closely together.+ 
Regarding the habits of X. aylographus, Mr. Hubbard mentions 
that it breeds only in dying trees, and generally only in trunks of large 
* *Naturgeschichte der Schadlichen Insecten,’ yon Vincent Kollar, Wien, 1837, 
p. 264; and English translation, called ‘Treatise on Insects,’ London, 1840, p. 257. 
t For figure, see p. 25 of Mr. Hubbard’s paper, previously referred to. 
