Mr. R. E. Turner on Fossorial Hymenoptera. 435 



6. Clypeus and labrum deeply longitudinally 



grooved on each side 7. 



Clypeus and labrum without grooves . . 8. 



7. Labrum with a narrow median groove at 



the base B.jlavifrons, Sm. 



Labrum without a median groove B, pect'inipes, llandl. 



8. Second and third joints of fore tarsus very 



strongly produced outwards ; basal 

 joint of intermediate tarsus dilated; 

 fourth dorsal segment with a pale 



fascia B. palmata, Sm. 



Second and third joints of fore tarsus 

 normal j basal joint of intermediate 

 tarsi not dilated ; fourth dorsal seg- 

 ment entirely black B. vespiformis, Sm. 



9. Second ventral segment with a raised 



transverse lamella B. lamellata, Handl. 



Second ventral segment with a longitu- 

 dinal carina or tubercle 10. 



10. Tubercle of the second ventral segment 



bih'd at the apex B.f areata, Erichs. 



Tubercle of the second ventral segment 

 not bifid 11. 



11. Sixth ventral segment normal, without a 



carina or raised triangular area .... 12. 

 Sixth ventral segment with a carina or 



raised triangular area 19. 



12. Intermediate femora serrate 13. 



Intermediate femora not serrate 18. 



13. Three basal dorsal segments with broad 



orange bands B. aureofasciata, Turn. 



Without orange colouring 14. 



14. Labrum and clypeus black 15. 



Labrum and clypeus yellow 17. 



15. The serration of the intermediate femora 



extending to the apex ; pale markings 

 on abdomen almost or quite obsolete . B.funehris, Turn. 

 The intermediate femora serrate in the 

 middle only ; pale markings of the 

 abdomen more developed 16. 



16. Black lobes of the basal joint of the fore 



tarsus well developed and clearly 

 divided, intermediate and hind legs 



mostly yellow B. atrifrons, Sm. 



Black lobes of fore tarsus not clearly 

 divided ; intermediate legs mostly, 

 hind legs wholly black B. severa, Sm. 



17. Serration of the intermediate femora well 



developed and extending to the apex ; 

 thorax and abdomen black, with a few 



narrow abdominal fasciae B. trepida, Handl. 



Serration of intermediate femora nearly 

 obsolete and not extending to apex ; 

 thorax and abdomen mostly yellow . . B. latifasciata, Turn. 



18. Abdominal fascias very broad, yellowish 



green ; sixth ventral segment emar- 

 ginate at the apex, seventh dorsal 

 segment sinuate at the sides B. nmrsupiata, Handl. 



