44() Mr. R. McLachlan’s Considerations 
TETRACANTHAGYNA VITTATA, Sp. 0. 
d 2. Face dingy olive yellow, labium shining blackish-brown, tips 
of mandibles black ; frons (excepting a line at the base) and vertex 
wholly blackish, the vertex with a strong anterior ridge, anda broad 
deep longitudinal groove, it is clothed with erect blackish hairs ; 
vesicle black ; antennae reddish, black at the base ; occiput black ; 
back of head blackish, but with an olivaceous orbital margin. 
Prothorax blackish, its hinder margin produced into a broad median 
obtuse lobe, and slightly excised on either side. Thorax brownish- 
black, clothed with greyish-brown hairs, the ante-alar sinus olive- 
brown ; anteriorly there are indications (at any rate in the @) 
of short narrow ante-humeral pale lines ; sides with two very broad 
greyish-yellow bands, one mesopleural, the other metapleural, 
separated by a still broader mesopleural band of the dark ground 
colour ; pectus blackish ; legs with dark reddish femora (black at 
the tips) and black tibize and tarsi, spines black, claws piceous. 
Abdomen robust, apparently wholly blackish, with no indications of 
markings in the dead insect (but in the somewhat immature 
d there is an indistinct olivaceous tinge). 
Wings comparatively narrow, the apex obtuse but somewhat pro- 
duced ; vitreous, but the anterior portion is occupied by a brownish- 
black vitta from the base to the pterostigma ; at the base this vitta 
is broad and its lower edge extends into the lower basal area, then it 
is limited by the upper edge of the principal triangle, then it occupies 
(partly in a fainter manner) the area between the subnodal and short 
sectors for some distance, then it is limited by the subnodal sector, 
then slightly invading the area between the nodal and subnodal 
sectors and then bounded by the principal sector as far as the 
pterostigma or slightly beyond ; in this vitta many of the areoles 
below the median nervure have a pale centre (but in a somewhat 
irregular manner), and most of the marginal nervules (at the base 
almost as far as the triangle) are pale, and in addition (especially 
in the costal area as far as the pterostigma) are also narrowly margined 
with pale ; costal nervure olivaceons (almost whitish in the some- 
what immature ¢), much incrassated towards the base ; neuration 
otherwise black, not very dense for the size of the insect ; 
pterostigma very small (4 mm.), brown (almost white in the some- 
what immature ¢); membranule whitish, well-defined ; subnodal 
sector fureating far before the origin of the pterostigma ; in the 
anterior wings there are about 34 ante-nodal and 23  post- 
nodal nervules, 8—10 hyper-trigonal, 7 in the lower basal area, 1 
in the inner triangle, 7 cellules in the principal triangle (the 
two inner divided by a longitudinal nervule in the 2, and 
