HYMENOPTERA. 15 



male, but much darker ; the hue takes a semicircular curve in 

 the centre, then a downward, and again an upward curve to the 

 lateral margin; the second segment transversely striated, the 

 apical one longitudinally so. 



Hab. Australia (Sydney). 



11. Thynnus insignis. B.M. 



Male. Length 15 lines. — Head and thorax black ; abdomen 

 reddish yellow ; the legs ferruginous ; the antennae black, the 

 scape ferruginous at the base and apex ; the clypeixs, labrum, 

 mandibles, and orbits of the eyes yellow ; the yellow line intei-- 

 rupted at the top of the eyes ; the tip of the mandibles black. 

 The thorax densely clothed with short silky white pubescence, 

 that on the metathorax longest; the posterior margin of the 

 prothorax and the tegulag yellow ; the vvings shghtly coloured. 

 Abdomen truncate at the base, and gradually tapering from 

 thence to the apex ; the extreme base black ; each segment with 

 a round ferruginous spot on each side, vmited by an arched 

 line of the same colour, which curves forwards to the basal 

 margin of each segment ; the apical margins of the segments 

 semitransparent, and having a beautiful radiating series of dark 

 hair-like lines springing from the basal margin of each segment ; 

 the apical segment with a semicircular space at its base striated 

 longitudinally, beyond this the striation is transverse. 



Hab. West Australia (Perth). 



12. Thynnus simillimus. B.M. 



Male. Length 15 lines. — This species is coloured like T. 

 Wallisii, with the following differences : the tegulse, prothorax, 

 and legs entirely black, but pubescent as in T. Wallisii; the 

 clypeus widely emargiate, the abdomen subtruncate at the base ; 

 the segments have a similar transverse upwards and downwards 

 curved ferruginous line, but the segments are pale beneath the 

 line ; the apical segment has a semicircular margined space at 

 its base, which is longitudinally striated ; the segment has a 

 curved striation beyond ; the margin of the lower ventral plate 

 is ciu'ved and enthe. 



Hab. Australia (Sydney). 



13. Thynnus vestitus. B.M. 



Male. Length 74 lines. — Black : the head and thorax densely 

 clothed with a white downy pubescence. The mandibles, cly- 

 peus, a line on the inner orbits of the eyes as high as the inser- 

 tion of the antennse, a narrow line behind them, and two oblique 



