Part I.] Beeson : Life-History of Diapus furtivus, Sampson. 15 
The writer has isolated ambrosia spores from the prothoracic pores of 
both sexes of Diapus furtivus, and has also observed the germination of 
the spores, while still attached to the globule of fat, after the beetle has 
commenced boring the entrance tunnel. The spores speedily become 
separated from the prothorax of the beetle once the insect is estab¬ 
lished in its tunnel, but, if galleries are opened up at the right moment 
the prothoracic pores may be seen by the naked eye very prominently 
marked in a white covering of newly grown mycelium. 
It is worthy of note that the female is much better provided with 
facilities for transport of the food fungus than is the male. 
Function of the Male Beetle. 
It has been mentioned above that the whole of the excavation of 
the galleries is carried out by the female beetle, and that the male very 
rarely co-operates in this work nor apparently does he assist in the care 
of the larvae and culture of the food-fungus. He is invariably to be 
found within the first half inch of the entrance tunnel, head directed 
inwards, occupied in protecting the entrance from the intrusion of 
enemies and in ejecting particles of frass and excrement. The method 
of ejection is somewhat striking and again illustrates that the peculiar¬ 
ities in the anatomical structure of this species are adaptations for a 
special function. The male beetle collects particles of wood-fibres, 
pellets of excrement and waste material, and conveys them to the end 
of the entrance tunnel, by pushing backwards with the hind end of the 
body. A small heap of the material is collected in the concavity at 
the end of the abdomen (formed by the dentate and setiferous edges 
of the elytra and the ridged terminal segment), and expelled from the 
wax-tube with a sharp jerk. The muscular effort in ejection is very 
considerable, and is often sufficient to throw small pellets several feet 
into the air. 
In consequence of this method of removing the frass, the waste 
material of the galleries is not accumulated directly at the base of the 
tree, but is scattered over the surrounding undergrowth in an area of 
several yards radius. A tree attacked by Diapus furtivus is readily 
recognizable from the layer of yellow dust which covers everything in 
its near neighbourhood. 
The boring dust consists of white fragments of wood-fibres ejected 
unchanged while the construction of the galleries is in progress. Unlike 
that of many other shot-hole borers, e.g., Xyleborus major , Xyleborus 
semigranosus, Platypus curlus, etc., the wood-dust is not pushed out 
[ 15 ] 
