162 THYNNIDJE. 



beneath the wings, the tegulae, the scntellum, postscutellum, and 

 the metathorax laterally at its apex, yellow ; the wings hyaline, 

 the nervnres black ; the legs ferruginous, the coxae black. Abdomen 

 shining ; the apical margins of the segments depressed ; the first 

 and fifth segments with narrow interrupted fasciae, the second, 

 third, and fourth segments with interrupted broader fasciae; 

 beneath with three more or less interrupted fasciae, these are 

 sometimes reduced to spots. 



Hob. Swan Eiver, Champion Bay. 



12. Thynnus oppositus. 



Male. Length 7| lines. — Black ; the abdomen with a double row 

 of ovate yellow spots above and also beneath. The clypeus trun- 

 cate, its anterior margin and also the mandibles yellow ; the pubes- 

 cence on the head and thorax white ; the tips of the femora, the 

 tibiae, and tarsi yellow; wings fulvo-hyaline, the nervures black. 

 Abdomen narrowed and rounded at the base ; the apical segment 

 yellow ; the second and four following segments with a large sub- 

 ovate lateral macula; beneath, the segments have similar rows 

 of maculae ; the terminal ventral segment with an acute spine at 

 the apex; the margin of the basal segment tuberculate in the 

 middle. 



Hob. Swan Eiver. 



In the type specimen the legs and the nervures at the base of the 

 wings appear to have been changed from yellow to red by cyanide 

 of potassium, used in collecting. 



13. Thynnus irregularis. 



Male. Length 6 lines. — Black ; the head and thorax with a few 

 minute yellow maculae ; the abdomen with irregularly shaped quad- 

 rate maculae laterally, and two rows of smaller maculae within. 

 Head very closely punctured ; the mandibles, the margins of the 

 clypeus, an oblong spot at its base, a small ovate spot above each 

 antenna, a narrow line at the inner margins of the eyes, as well 

 as a short one behind them, towards the mandibles, yellow. 

 A narrow line on the anterior margin of the prothorax, a short 

 line in the middle of the mesothorax and at the margin of the scu- 

 tellum, and a minute spot on the posts cutellum, yellow; wings 

 subhyaline, the nervures black. Abdomen with subquadrate ma- 

 culae laterally, and between these two rows of small lunate or 

 hooked-shaped spots close to the apical margins of the segments ; 

 on the basal segment these spots unite with the lateral ones ; 

 beneath, the second, third, and fourth segments have each two 

 large white ovate maculae, the maculae having a transverse curved 

 black line. 



Hdb. Swan Eiver. 



