THE 
Essex Naturalist: 
BEING THE 
3ournal of tbc £ssey jftelb Club, 
EDITED BY 
WILLIAM COLE, A.L.S., Honorary Secretary , 
MILLER CHRISTY, F.L.S., 
and 
PERCY THOMPSON, F.L.S , Honorary Secretary. 
*. / 
VOLUME XIX. 
MAY 1918 to APRIL 1921. 
“ Men that undertake only one district are much more likely to advance 
Natural Knowledge than those that grasp at more than they can possibly be 
acquainted with. Every kingdom, every province, should have its own 
Monographer.”— Gilbert White, oi Selborne. 
“ Things seen are mightier than things heard." —Tennyson, 
i 
[The authors alone are responsible for the statements and opinions contained in their 
respective papers.] 
JSfrafforb, (Bbbcx : 
THE ESSEX FIELD CLUB, AT THE ESSEX MUSEUM 
OF NATURAL HISTORY. 
1921. 
