2i 4 THE HUMBLE-BEE 



4. PSITHYRUS BARBUTELLUS, Kirby. 



QUEEN. Of medium size; length 17-19 mm., ex- 

 panse 36-39 mm. ; sometimes smaller. 



Head black, with some dull yellow hairs on top. Thorax 

 black, with a dull yellow band in front and a narrow one 

 behind. Abdomen black, with sometimes some dull yellow 

 on the 1st segment, and with the 4th and 5th segments, 

 sometimes also the edge of the 3rd segment, white. 



The 6th dorsal segment has a dull shine, is punctured, 

 and bears a faint raised line down its centre. 



The elevations on the 6th ventral segment form a trans- 

 verse, crescent-shaped mark, which does not nearly reach to 

 the apex of the segment, and has a narrow division in the 

 middle ; between the crescent and the apex the segment 

 is clothed with short velvety golden-brown hairs. The 

 crescent-shaped elevation affords an easy means of dis- 

 tinguishing this species from all others. 



Male. Length 15-16^ mm., expanse 29-32 mm. 



Head black, with some yellow hairs on top. Thorax 

 black, with a yellow band in front and a narrow yellow band 

 behind. Abdomen black, with the 1st segment more or less 

 yellow ; the 4th and 5th segments white ; the 6th white at the 

 sides, black in the middle ; 7th more or less black. The 

 white often extends on to the 3rd segment. 



The coloration is therefore very like that of Ps. dis- 

 tinctus, except that there is no definite tinge of yellow on 

 the sides of the 3rd segment ; in very fresh specimens, how- 

 ever, the white area is sometimes faintly tinged at its base 

 with yellow, but this soon fades away. 



Coat uneven rather shorter than in distinctus ; the 

 hairs slightly stiffer, slightly coarser, and slightly less 

 dense than in distinctus. 



On the 6th ventral segment, near the apex, there is a slight 

 mound on either side of the middle. 



Hind metatarsi more slender and longer than in dis- 



