86 RHYNCHOPHORA. 
and the large majority of Pityophthori. They are also diagnostic of the female in 
Platypodides. In a Holarctic genus of Hylesinides, Polygraphus, there is disagree- 
ment as to the external indications of sex, and further evidence on them is required. 
It therefore appears that in all Scolytids (except Trypodendron) known to be wood- 
borers, as well as in those Tomicids most nearly allied to them, such characters, as far 
as is known, are entirely female. 
Two exceptions recorded—Dendroctonus terebrans ( Oliv.) and Pterocyclon fasciatum 
(Say)—are of slight importance. The latter species is normal in all essential 
characters. 
The one notable exception which lends credence to Hopkins’s statement, that the 
characters may be reversed in species of the same genus, is Pityophthorus minutissimus 
(Zimm.). 
This insect and its allies—P. pubipennis, Lec., P. pilosulus, Lec., &c.—present well- 
defined structural differences from most species of Pityophthorus. Though the genus has 
not yet been sufficiently studied to be subdivided, it is certainly composite, and in that 
rather than in the non-validity of the sexual characters within a genus must the 
explanation of this anomaly be found. 
‘There are as yet no sufficient grounds for supposing that well-marked characters, 
such as an enlarged or ciliate antennal club, an excavate front, or more strongly spinous 
elytra, are not confined to the same sex within generic limits. 
Terminology. 
The expressions “ outer” and “ inner” have been used loosely by most writers to 
indicate indifferently the faces and the borders of the tibia or of a flattened antennal 
club. 
In descriptions of the antenna the terms “ outer » and “inner” are retained here for 
the faces of the club when flattened. If such an antenna is extended forwards from 
the head the outer face looks obliquely downwards, the inner upwards; the border 
of the club nearest to the middle line and to its fellow is the lower or inferior border ; 
the opposite border, which is on the same side as the salient angle of the scapo- 
funicular articulation, is the wpper or superior border. . 
In descriptions of the tibie the outer face is the posterior surface of the fore tibiz, 
the anterior surface of the middle and hinder tibia, when the limbs are extended at 
right angles to the body-axis ; the other is the inner face. The border which is 
continuous with the superior femoral border and is usually dentate is the upper or 
superior border, the other is the lower or inferior border. 
I limit the term striato-punctate to such elytra as have the main rows of punctures 
feebly or indistinctly impressed ; but when no impression whatever can be seen with 
