Part I.] Beeson : Life-History of Diapus furtivus, Sampson. 9 
felled trees on felling areas, fresh wind-falls, trees on the point of death, 
or very much weakened by disease or the attack of primary insects. 
The flight is weak and jerky and the beetles may easily be captured 
in a net or open killing-bottle. Both sexes swarm at the same time, 
though there is a tendency towards the earlier emergence of the males. 
The swarm periods are not sharply marked, as the emergence of indivi¬ 
duals of a brood goes on for several weeks and the broods of successive 
generations overlap (see later under Seasonal History). The beetles, on 
arriving at a tree, settle on the bark and run about actively searching, 
under flakes of bark and in crevices, for a suitable site for the entrance 
tunnel. Stebbing (1914, p. 631) makes the following comment in this 
connection. “ This little beetle differs from most platypids owing to 
its great activity.” In the experience of the writer, however, Diapus 
furtivus does not appear to differ much from its associates in the matter 
of activity during the flight period. All Platypodidae which attack 
the Sal, are able to progress actively over the bark surface, and it may 
be noted that the period, prior to the boring of the entrance tunnel, is 
practically the only occasion on which the beetles make use of their 
tarsi. When living inside the tree and moving about in the galleries 
the long slender tarsi are folded back behind the tibiae and the beetle 
walks on the spurs at the apices of the tibiae. If Platypodid beetles 
are removed from their galleries, after they have lived in them for several 
weeks, they are found to be very helpless on their legs and appear to 
have lost the power to straighten out the tarsi. In many cases the 
tarsi are missing or have lost three or four joints. 
The Entrance Tunnel and Wax-Tube. (Plate II, figs, a, b.) 
The longitudinal cracks in the bark are invariably chosen, in the 
first place, for the site of the entrance tunnel, but, in the case of a heavy 
attack, entrance holes are bored on the flat interspaces as well. From 
20 to 30 holes may occur in the same vertical line of a foot in length, 
but, while the distance between two holes is often less, the average is 
half an inch. 
The entrance hole of this species is marked by a curious structure 
which, with one exception, is unique. Projecting from the bark for a 
distance of Jth to Jth of an inch and in direct continuation of the walls 
of the tunnel is a slender tube of white wax of papery thickness, finished 
off smoothly on the inner and outer surfaces (Plate II, a, a). The 
nearest analogous structures are the pitch tubes of the North American 
bark-beetles of the genus Dendroctonus and the ring of gum and wood- 
dust surrounding the entrance holes of some species of Platypus in India. 
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