415 
DIAPUS sp. prox. IMPRESSUS. 
Plate XXIV, figs. 3, 34. 
Classification :—Order, COLEOPTERA. Family, Scolytide. Subs 
Family, Platypini. 
Tree attacked :—Quercus incana. 
Beetle.—This beetle resembles D. impressus but is much 
larger, being 5-5°4 millim. in length. The colour is darker red, 
the thorax being entirely of this colour as are the legs, with 
the exception of the tarsi which are lighter brown. The front 
of the head is only very finely pitted in the male but strongly 
punctured in the female. The thorax is strongly constricted at 
the sides behind the middle and has no median line. The 
apical margin of elytra is concave in male and in female truncate, 
with the outer edges produced into teeth curving inwards. 
The abdomen is concave behind in the female. Figs. 3, 3a 
show the male and female of this insect. 
Life-History. 
This insect is to be found on the wing at the commencement 
of June at elevations of about 6,000 feet. At that period it tunnels 
into the wood of oak trees for egg-laying purposes. The beetle 
appears to choose trees the wood of which is nearly or quite dry, 
and bores down into the heart-wood through the thickest bark. 
Externally their presence can be recognised by the rings of 
sawdust surrounding the circular entrance hole. The tunnels 
are either quite straight or may be slightly curved: but, as far 
as present observations go, they do not appear to branch at 
all, Both beetles and larvee were discovered at the bottom 
of the tunnels, no offset borings having been made to lay 
the eggsin. Asin the case of the Deodar Crossotarsus the 
beetles appear to live for some time after laying their eggs, 
and are to be found moving up and down the tunnel the 
head pointing inwards, As in the case of this latter insect this 
Diapus is an ambrosia beetle. The sides of the tunnel 
throughout are discoloured by a fungus growth upon which the 
grubs were apparently feeding. The beetles appear to finally 
