SCOLYTUS MINOR, MS. 209 

portion left free of them varyingin length according to the 
length of the egg gallery, but they are always made right up to 
its extreme end, @.¢., the beetle ceases boring as soon as she 
has laid her last egg. Asthe Scoly¢us carries on her gallery, 
she shovels back the wood-dust with her feet, a large quantity 
of it being also apparently passed through the alimentary canal 
since round masses of chewed wood are constantly being passed 
out at the anus. These are apparently covered with some 
siccable substance and are detached by, and remain fixed for 
atime to, the hind tarsus, They may contain an egg and be 
placed by the tarsus into one ofthe recesses. My observations 
have not been sn fficiently extended, however, to enable me to 
make this statement definitely at present. When the beetle has 
finished its egg-laying, it does not die, as is the case with many 
bark-beetles, but remains in the gallery or entrance hole, both of 
which are kept absolutely free of wood-dust,etc. If dusc be 
_ pushed into this, she at once begins to shovel it out and get the 
tunnel clear again. In this the Scolytus differs from the blue 
pine Tomicus, which dies at the end of its egg gallery as soon as 
all the eggs are laid. I have found the Sco/ytus suill alive in the 
tunnel when most of the larve from the eggs laid by her have 
become full grown and one or two changed to pupe. This is 
probably with a view to protecting the egg and larva from 
predaceous insects, as, when the @ dies, she does so in her 
entrance hole, the top of the abdomen being generally visible 
from outside, and thus effectually blocks it up. It does not, 
however, prevent the flat pink C/lerus larve from getting to her 
offspring as the former move about between the bark and 
sapwood with ease. Theeggs would appear to take but a few 
days to develop since those at the bottom of the tunnel, ae 
those first laid, hatch out into young larve before the mother 
beetle nas finished boring the egg gallery and laying the eggs 
higher up. Between 4o and 50 larve hatch out, but the number 
is at times fewer. 
The grubs bore away from the mother gallery in a direction 
which in the middle of the tunnel is at right angles to it, and 
trends away from the right angle in an upward direction above 
and in a downward one below the centre tseerBliax, fig. 3, d (2)). 
A uniform and almost invariably constant pattern is thus 
