Pe  ROMBUS LATREILLELLUS — 183 
from the other by the following characters :—the slightly 
shorter cheeks of /atrezllellus ; the shorter coat of atrezt- 
Jellus, most noticeable on the Ist segment of the abdomen, 
especially if there are yellow hairs there; the narrow 
yellowish or brownish fringe on the edge of the 2nd seg- 
ment, almost always present in /atrez/lellus, but seldom in 
vuderatus ; and lastly, a very conspicuous distinguishing 
character which, although it is not mentioned by Smith 
or Saunders, holds good in every specimen I have 
examined. This is in the relative widths of the yellow 
bands on the thorax. In Zatrezllellus the band at the back 
of the thorax is much narrower than the band at the front, but 
in vuderatus the bands, measured across the middle, are 
approximately of equal width. 
WoRKER.—Large; length 12-18 mm. 
Resembles the queen, but the yellow band on the 
back of the thorax is sometimes absent, and in small 
specimens there is generally no trace of yellow on the 
Ist segment. 
MALE.—Rather large; length 15-16 mm., expanse 
28-31 mm. Abdomen rather elongate. 
Pale yellow with a greenish or brownish tinge, with the 
exception of the following black markings. The head 
black, except on the top and in the middle of the face. 
A black band across the thorax between the wings. A black 
band across the 2nd segment of the abdomen, and another, 
generally narrower, across the 3rd segment; these bands are 
separated by a narrow band of greenish-white on the 
edge of the 2nd segment; 6th segment black in the 
middle, 7th segment black. This colouring resembles 
that of Pszthyrus campestris male, the description of which 
should be consulted. 
In light specimens the black bands on the 2nd and 
3rd segments are reduced or absent, the 6th segment is 
entirely yellow, and the 7th partly so; in the lightest 
specimens, however, there are always some black hairs on 
the 2nd segment, chiefly at the sides, although they are 
