Scolytide. | RHYNCHOPHORA. 403 
reception of the logs; eyes round, subconvex ; head broader 
than thorax . te pew he Us jccu ei pe ay, , Kags SAY PODIN EE, 
SCOLYTINZA. 
This sub-family contains the whole of the genera of the Scolytide with 
the exception of Plutypus, from which it differs as above stated; the 
shape of the various geuera is somewhat variable but is almost always 
cylindrical; in the subdivision into tribes and species good characters 
are afforded by the sculpture of the ‘thorax, which is in many cases 
furnished with strong warty asperities in front, and by the formation of 
the apex of the elytra which is often more or less excavate and, in one 
sex at least, dentate; the shape of the club of the antenne and the 
number of joints of the funiculus of the antenne are also of great im- 
portance. 
The sexual differences are in many cases very marked, the males in 
some instances differing entirely from the females and being extremely 
rare. Our species may be divided into the three following tribes :— 
I. Thorax not prolonged over the head which is always in part 
visible from above and is terminated by a short snout ; thorax 
without any marked asperities on its anterior portion; third 
tarsal joint nearly always bilobed.* 
. Abdomen strongly raised obliquely from near apex; thorax 
Mis eae atsides. . . - SCOLYTINA. 
. Abdomen not, or only slightly, raised, as a ‘rule regularly 
ieaaeent thorax not bordered at sides. . HYLESININA. 
II. Thorax prolonged over the head, which is sunk in the thorax 
when the insect is at rest, and is more or less globose ; thorax 
almost always furvished with more or less distinct warty 
asperities in front ; third tarsal joimt simple . . . . . . DRyYOCHTINA, 
SCOLYTINA. 
This tribe comprises the single genus Scolytus, which may easily be 
known by the shape of the abdomen and by its short broad form, pro- 
jecting head, and the absence of asperities in front of the thorax, which 
is usually finely punctured, and very shining; the thorax is margined 
at sides and base ; the scutellum is distinct and sunk in a deep impres- 
sion, and the elytra are not excavate and only slightly sloped at apex ; 
the antenne are inserted near the eyes and are 11-jointed, with a large 
club which is longer than the funiculus ; the latter is composed of seven 
joints ; the tibia are armed externally with a strong hook and the third 
joint of the tarsi is broad and strongly bilobed ; the posterior cox are 
rather widely distant; the species are very destructive to trees, and 
appear to attack especially the elm, oak, hornbeam and birch, besides 
various fruit trees; none of them appear to attack Conifere. 
* This character is indistinct in the smaller species of Hylesinus, and is absent only 
in one genus, Polygraphus ; in the Dryocwtina there may occasionally be a vestige of 
a snout, but it is not found in any indigenous genus, 
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