416 RHYNCHOPHORA. [ Hylesinus. 
the case of H. fraxini, as observed by Dr. Chapman, the female is 
often bulkier when the burrow is half completed than on entering it, 
and the eggs laid by a single beetle must often exceed in aggregate mass 
the original bulk of the female. The eggs are laid along both sides of 
the burrows, usually at very regular intervals, in little hollows dug out 
to receive them; they are covered with a gummy material, which soon 
gets a coating of fine frass; the gallery is finished and the eggs laid in it 
in from ten to twenty days ; when the task of oviposition is finished both 
beetles usually die in the burrow; the female always does so ; the dead 
beetles may still be found lying in the burrows after several years; the 
larve are straight, white, footless fleshy grubs, with a rather large head 
and powerful mandibles, and appear to hatch out towards the end of 
May. In the autumn they assume the pupa state, and shortly after- 
wards emerge as perfect insects. In cases where the beetles attack 
young trees it is a good plan to rub a good coat of soft soap into accessi- 
ble parts of the tree by means of a common scrubbing-brush ; some 
authorities are of opinion that it is the want of dying timber that forces 
them to attack the live trees, and advise that the old trunks should be 
left as traps, whereas others consider that these harbour the beetles, and 
advise their removal; if the old trunks or pieces of trunks are burnt at 
intervals, it is probable that the plan of leaving them on the ground will 
be found to be of service. 
Dr. Chapman has made an important observation with regard to H. 
crenatus, viz. that it takes two years to undergo its transformations, the 
larve assuming the pupal state at the end of the second summer; as 
felled timber would be unable to support this long larval existence, the 
beetle is never met with except in living trees, and, while an affected 
tree continues alive, they appear never to desert it for another ; “they 
economise it,” Dr. Chapman says, “as much as possible, the destroyed 
bark being more completely riddled and devoured by them than by any 
other beetle of the family I am acquainted with; the burrows of the 
larve are much more irregular also, so that it is impossible to find one 
of those perfect maps of their voyages (as in H. fraxint), which have 
earned for the Xylophaga as a family the name of ‘ typographers.’ ” 
H. vittatus attacks fallen elm, as H. fraxini does theash; its burrows 
are shorter, and the two branches are very uniformly of equal length, 
rarely exceeding 2 of an inch long; the number of eggs laid is seldom 
as many as twenty, and, being usually placed more widely apart 
than those of H. fraxini, the burrows of the larve are nearly parallel ; 
the species never appears to attack live trees and is therefore unimpor- 
tant from an economical point of view. 
It should be remembered that all these beetles that bore into the solid 
wood play a most important part in clearing the ground of dead trees: 
this is especially the case in the tropical forests, which would utterly be 
choked up and destroyed in the course of ages but for the insects that 
drill holes into them which admit the moisture that causes them to 
