2io THE HUMBLE-BEE 



3. PSITHYRUS DISTINCTUS, Perez. 

 Closely related to and much resembling Ps. vestalis. 



QUEEN. Smaller than Ps. vestalis ; length 18-20 mm., 

 expanse 36-39 mm. ; sometimes smaller. 



The coloration resembles that of Ps. vestalis, but the tint 

 of the yellow band on the front of the thorax is lighter and is 

 best described as dull lemon ; this band is always broad : 

 sometimes there are a few pale yellow or yellow-tipped 

 hairs behind the wings and at the back of the thorax. 

 On the back of the thorax and on the edges of the 1st and 

 2nd segments of the abdomen the black shades into dark grey 

 (brown in faded specimens) or sometimes into a paler 

 tint. The yellow at the sides of the 3rd segment is very pale 

 and soon fades to white. 



A giant specimen from Aviemore, in the Saunders' 

 Collection, has a narrow yellow band on the back of the 

 thorax and the 1st segment of the abdomen yellow on the 

 base at its sides. 



The coat is denser and, in proportion to the size of 

 the insect, somewhat longer than in vestalis. The meta- 

 tarsi of the hind legs are somewhat shorter than in 

 vestalis : in distinctus the length of this joint is equal to 

 that of all the tarsi together, but in vestalis it is somewhat 

 longer than these. 



The 6th dorsal segment (seen through a good lens) is 

 very faintly and shallowly punctured ; in vestalis it is 

 more deeply punctured, especially at the sides. 



The elevations on the sides of the 6th ventral segment 

 are shaped very much as in vestalis, but they are rather 

 higher towards the apex and the golden hairs there are 

 shorter. 



Male. About the same size as vestalis ; length 1 5- 

 17 mm., expanse 29-32 mm. 



Coloured like vestalis, except that the yellow on the head 

 thorax, and base of the abdomen is of a lighter tinge, almost 

 sulphur-yellow in fresh specimens, and is more extensive. 



