E. Y. Thomson, J. Bell and K. Pearson 
49 
was easier. The change of district was due to the fact that we found at Gerard's 
Cross in Dr Alice Lee a ready helper, who organised in association with the local 
schoolmaster a comprehensive search party. Mr 0. H. Latter of Charterhouse 
most kindly went through the material to exclude members of other races. 
The microscopic measurements made by Miss E. Y. Thomson followed very 
closely the lines indicated in the earlier paper, an ocular micrometer and a Leitz lb 
objective being used. The magnification in her case was one ocular unit = r46 mm. 
As this differs slightly from the value used by Miss Wright*, the measurements 
of both series when compared together in this paper have been reduced to 
absolute values. 
(2) Characters measured. 
These are precisely the same as those of the first study, and the cuts of that 
figure reproduced below indicate the lengths measured. 
Right Wing. Vespa l/uigans. 
X I 
Left Wing. Veapa l^ulgans. 
X 
Y 
(A) Total length of wing reckoned from the tip of wing outside of cell i to 
the inside of the vein at the end of cell b. Cf Figs. 1. and IL 
* The setting of the microscope differed sHghtly. 
Biometrika vii 7 
