210 THE HUMBLE-BEE vill 
3. PSITHYRUS DISTINCTUS, Pérez. 
Closely related to and much resembling Ps. vestadzs. 
QUuUEEN.—Smaller than Ps. vestalis ; length 18-20 mm., 
expanse 36-39 mm.; sometimes smaller. 
The coloration resembles that of Ps. vesta/zs, 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 Ist 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 vestalzs. The meta- 
tarsi of the hind legs are somewhat shorter than in 
vestalis ; in adzstenctus the length of this joint is equal to 
that of all the tarsi together, but in ves¢alzs it is somewhat 
longer than these. , 
The 6th dorsal segment (seen through a good lens) is 
very faintly and shallowly punctured; in vestalzs 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 vesta/zs, but they are rather 
higher towards the apex and the golden hairs there are 
shorter. 
MALE.—About the same size as vestalzs; length 15- 
I7 mm., expanse 29-32 mm. 
Coloured like vesfa/zs,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, 
