140 Proceedings of the Royal Physical Society. 
probably more appropriate than was intended. The boring is begun by the 
female, which cuts out a crutch-like tunnel about 4 inch to 3 inch in length. 
The male is not always present at this operation, bie if he is, he clears away 
all the bore meal. Once the crutch is finished he joins his mate inside the 
crutch, and she now begins the brood- or mother-gallery proper. The male 
again acts as scavenger until 4 inch to 1 inch of the mother-gallery is cut. 
At this stage he cuts a small niche at the side of the gallery. The female 
continues her boring a little farther. She then returns and nibbles the sides 
of her tunnel and, depositing her eggs, embeds them in the dust she has made 
in nibbling. She then returns to the end of her tunnel and begins boring 
afresh, the male removing the frass she passes back to him. The portion of 
the gallery occupied by the eggs is lined with bore meal, and the eggs are 
further protected by slimy threads which eee serve to consolidate the 
frass surrounding them. 
The Hatching of the Egg—The eggs of H. ater are comparatively long in 
hatching, the period varying from a fortnight to three weeks (11th May to 
30th May). My observations indicate that the later laid eggs hatch in a little 
less time than the first laid. 
The newly hatched larvee at first crawl about the frass surrounding them. 
They then start boring at right angles to the mother-gallery; later hatched 
larvee apparently take advantage of the tunnel cut by the earlier hatched 
ones. On the third day after hatching, the complex of larval tunnels extends 
to } inch distance from the mother-gallery. This complex consists at first of 
two or three fine tunnels at right angles to the mother-gallery, then these 
lines become confused and a complex network or a large cut-out space only 
is to be seen. A fortnight later this network or space is extended, and from 
its distant margin distinct individual tunnels arise wihce later terminate in 
the pupal chambers. 
Duration of Egg-laying and Cutting of the Mother-gallery.—The cutting of the 
mother-gallery and the laying of the eggs by H. ater is of long duration, extend- 
ing over six to seven weeks (1st May to 27th June). It is interesting to note 
that egg-laying ceases approximately with the pupation of the larve hatched 
from the first laid eggs. The average number of eggs per gallery is 120. 
Duration of the Larval Stage—Hight to nine weeks (22nd May to 20th 
July) is the duration of the larval stage. Of these six or seven are devoted 
to feeding and the remainder to resting prior to pupation. ee 
Duration of the Pupal Stage —This is of short duration, varying from nine 
to eleven days (20th July to 51st July). 
Total period from Egg to Adult.—The total period from egg to adult is 
from two to three months’ duration (11th May to 31st July). 
