2o6 THE HUMBLE-BEE 



1. PSITHYRUS RUPESTFJS, Fabricius. 



Quekn. Large; length 20-23 mm., expanse 40-45 

 mm. ; sometimes smaller. 



Black, with the 4th and following segments of the abdomen 

 red. The red is less bright than in B. lapidarius. 



There is occasionally a dingy yellowish-grey band 

 across the front of the thorax. 



Wings dark brown, thus darker than in any other 

 species. 



The 6th dorsal segment is dull and is covered with 

 very short red hairs. 



The elevations on the sides of the 6th ventral segment 

 are very prominent and form angular wings, which pro- 

 ject so far that they can be seen plainly on either side 

 when the tip of the abdomen is viewed from above. 



MALE. Length 15-17 mm., expanse 30-33 mm. 



Head black. Thorax black, usually with indistinct 

 yellowish-grey bands in front and behind. Abdomen black ; 

 with the sides and edges of the 1st and 2nd segment usually 

 more or less yellowish-grey, and with the 4th and follow- 

 ing segments red. The red usually extends on to the 

 3rd segment where it shades into the black ; it is less 

 bright than in B. lapidarius. In some specimens there is 

 no yellowish-grey on the thorax and abdomen. 



Coat rather long, uneven, and rather coarse. 



Antennae rather short ; length of flagellum 5 mm. 

 This species may be easily known from the male of B. 

 derhamellus, which in coloration it much resembles, by 

 the thicker and shorter antennae and somewhat loneer 

 coat. The antennas are thicker than in B. lapidarius. 



Armature distinct. 



A specimen of the male sent me from Colchester is entirely 

 black. Another taken at Ripple has the abdomen red except the 

 1st segment. 



This large species is parasitic on Bovibus lapi- 



