Mr. E. E. Turner on Fossorial Hymenoptera. 299 



XXXII. — Notes on Fossorial Hymenoptera. — XXI. On the 

 Australian Larrinse of the Genus Tachytes. By iiOWLAND 

 E. TuRNEK, F.Z.S., F.E.S. 



Key to the Australian Sj>ecies 0/ Tachytes. 



1. Abdomen wholly bright testaceous or 



ferruginous red 2. 



Abdomen black, at most the apical margins 

 of the segments or the apical segment 

 brown or ferruginous 3. 



2. Abdomen bright testaceous ; pubescence 



of thorax and median segment golden ; 



legs bright testaceous T. formosissimus, Turn. 



Abdomen ferruginous red ; pubescence 

 wliite ; legs black, the tarsi more or less 

 ferruginous T. rubellus, Turn. 



3. Pubescence of the abdomen deep or pale 



golden 4, 



Pubescence of the abdomen silver, that on 

 the pjgidial area sometimes golden .... G. 



4. Outer margin of the basal joint of the fore 



tarsus with five spines; second joint of 

 the ilagellum scarcely longer than the 



third T. approximatiis, Turn. 



Outer margin of the basal joint of the fore 

 tarsus with six spines ; second joint of 

 the fiagellum distinctly longer than the 

 third ,5. 



5. Legs almost entirely black ; median seg- 



ment nearly half as long again as the 



scutellum T. plutocraticus, Turn. 



Tibine, tarsi, and the apex at least of the 

 femora bright testaceous brown ; median 

 segment very little longer than the scu- 

 tellum _ T. relucens, Turn. 



6. Tibise, tarsi, and sixth dorsal segment 



ferruginous T. mitis, Turn. 



Legs, e.xcept the apical tarsal joints, black; 

 sixth dorsal segment black 7. 



7. Pubescence of the pygidial area golden and 



dense 8. 



Pubescence of the pygidial area not golden, 

 either silver and dense or fusco-ferru- 

 ginous and very sparse 9. 



8. Pygidial area very broadly rounded at the 



apex, almost truncate ; basal joint of fore 

 tarsus with six spines on the outer.margin. T. (estuans, Turn. 

 Pygidial area narrowly rounded at the apex, 

 almost triangular ; basal joint of fore 

 tarsus with live spines on the outer 

 margin T.fatalis, Turn 



