1(51 inYNNTlKI';. 



16. Thynuus aterrimus. 



Muh. Len<?th (> linos.— Black ; shorter and broader than is usual 

 in Thynnideous insects. The face and body beneath with cinereous 

 ])iil.oscence ; the prothorax with tlie anterior margin very narrowly 

 yellow ; the po.stscutellum and a very narrow line continued to the 

 posterior wings yellowish ; wings fusco-hyaline, the ncrvures black. 

 The head and thorax vcrv closely punctured. Abdomen shining, 

 and having very shallow 'distant punctures; the segments deeply 

 constricted ; the termuial ventral segment tridcntate. 



JIab. Swan River. 



17. Thynnus perplexus. 



Male. Length G lines.— Black ; the head and thorax with yellow 

 markings, the abdomen with interrupted yellow fasciae on each 

 segment; the legs ferruginous. The mandibles, the olypeus, a 

 spot above each antenna, and two minute spots on the vortex, 

 yellow. The posterior margin of the prothorax, the tegula^ an 

 ovate spot on the mesothorax, and also one on the scutoUum, 

 yellow ; the femora and thorax beneath with white pubescence, as 

 well as the sides of the metathorax ; wings hyaline, the nervures 

 ferrugmous. Abdomen with six interrupted yeUow fascia), the 

 seventh segment ferruginous, the inferior plate forming a tri- 

 angular appendage ; beneath ferruginous ; the margins of the seg- 

 ments black ; the second and three following segments with two 

 large ovate maculae. 



Female. Length 5 lines.— Head, thorax, and legs ferruginous ; the! 

 bead wider than the thorax, and with a few scattered punctures. 

 Abdomen black above and ferruginous below; the basal segment 

 yellow above, black at the extreme base, and with a narrow black line 

 in the middle ; the second segment transversely striated, and with a [ 

 largo lateral subquadrate spot ; the three following segments with 

 veiy broad yellow fasciae, slightly interrupted in the middle. 



Hab. Swan River. 



18. Thynnus petulans. 



3Iale. Length 9 lines. — Head and thorax closely punctured and 

 black; abdomen, tibiae, and tarsi ferruginous. The mandibles J 

 reddish yellow, their apex and inner margin rufo-piceous ; the 

 clypeus truncate, its margin yellow, and emitting upwards a 

 yellow triangular mark in the middle. The posterior margin 

 of the prothorax and the tegulae ferruginous; the metathorax 

 with white woolly pubescence; wings pale fulvo-hyaliue, the 

 nervures dark ferruginous; beneath with white pubescence, thai 

 legs fringed with, the same. Abdomen with the extreme base I 



