146 THE THYNNIDEOUS INSECTS OF AUSTRALIA. 
Thynnus, but having the head twice as broad as the thorax (which 
is tripartite), the sides of the mesothorax furnished ‘ processu 
aleeformi”); the maxillary palpi 6-jointed, with the joints subzequal, 
and the tarsal ungues simple. The type A. bicolor is 5 lines long. 
The following is its specific character given by Dr. Erichson, 
together also with those of his four species of Thynnus :-— 
Ariphron bicolor.—Rufus, capite piceo, abdomine nigro apice rufo. Long. 5 lin. 
Thynnus Olivieri.—Mas.; niger, pedibus rufis, thorace supra fulvo villoso, abdomine 
supra 4—, infra bifariam flavo-maculato. 
Frm.—Rufa, capite subgloboso thoraceque immaculatis'abdomine piceo, segmentis 1—5. 
4-fariam flavo-maculatis, 1. levissimo. Long. 73 lin. 
Thynnus, senilis. — Niger, albido-villosus pedibus concoloribus, clypeo flavo. (Mas.) 
Long. 54—73 lin. 
Thynnus fervidus. — Niger, clypeo, mandibulis scutelloque flavis, thorace rufo-vario, 
abdomine pedibusque rufis. (Mas.) Long. 6% lin. 
Thynnus humilis. — Niger, cinereo-hirtellus mandibulis testaceis abdominis segmentis 
exolete flavo-marginatis, secundo transversim bicarinato. (Fem.) Long. 33 lin. 
