REPORTS BY THE HONORARY SCIENTISTS. 313 
is captured fixed to the tree, from which it has been unable to 
withdraw its ovipositor. 
The Dunraven specimens of jwvencus were from an Austrian 
pine, and the Haddo specimens from a large dead Scots fir felled 
about January 1897. 
The life-history of the Szvex species is as follows :—The female, 
by her long and strong ovipositor, bores a hole through the bark 
into the alburnum or sapwood of standing sickly trees or blown 
or felled timber. This she does very quickly. Mr Mitchell, who 
kept some jwvencus in captivity, watched them boring and laying 
their eggs. In some notes sent on to me he describes his obser- 
vations :—‘‘On closely examining the bark, and still better the 
timber under the bark, the holes made by the ovipositor are 
easily found. They are usually single or in groups of two or 
three, and have a small raised collar round them, the result of 
the accumulation of bore-dust between the bark and the wood. 
They are sometimes as much as } inch deep, including + inch of 
bark. The usual depth for the most successful hatching is about 
+ inch or slightly over, 7.e., as deep as the second or third layer 
of wood. The wood-wasp about to deposit first wanders all over 
the log, the point of the ovipositor in its sheath dragging against 
the bark, and the antennz working vigorously until a suitable place 
is found. The actual operation of boring takes about four minutes. 
When the borer is full down there is a halt for a moment, and a 
heaving sort of movement, during which, presumably, the egg 
is passed. The insect, in the six or seven days of its life, makes 
from a hundred to about one hundred and fifty borings.” 
At each boring one egg is laid, from which comes a whitish 
grub, which, when full grown, measures over an inch in length. 
It is round, and has three pairs of very small thoracic feet, and 
strong, biting jaws. A spine projecting from the last segment is 
also characteristic. This spine, and the cylindrical shape of the 
larva, will serve to distinguish it from the larve of the Ceramby- 
cide, or ‘‘long-horned ” beetles, which are somewhat flattened and 
have no spine. 
The hatched out grub, “after following the same layer of wood 
for about three-eighths to three-quarters of an inch, increasing 
rapidly in bulk meanwhile, then turns inwards towards the 
centre of the tree,” and later on curves out again towards the 
surface, so as not to leave too great a thickness of wood to be 
bored through by the imago when ready to escape. As the larva 
VOL. XV. PART III. 2¢ 
