NOTES ON BRITISH THYSANOPTERA. 221 
EXPLANATION OF DIAGRAMS. 
. Left edeagus-guide of H. alveus in the lateral aspect. 
. Right edeagus-guide of H. alveus in the cephalo-vertical aspect. 
Left edeagus-guide of H. armoricanus in the lateral aspect. 
d, Right edeagus-guide of H. armoricanus in the cephalo-vertical aspect, 
Figures c and d@ from an original Norfolk example. 
aos 
Colesborne, Cheltenham, 
September 13th, 1916. 
BIOLOGICAL AND SYSTEMATIC NOTES ON BRITISH 
THYSANOPTERA. 
By C. B. Winuams, M.A., F.E.S. 
(The John Innes Horticultural Institution, Merton, Surrey, England.) 
Tue notes below include the descriptions of four British 
species of Thysanoptera hitherto undescribed, records of three 
new to the British Fauna and notes. on the life histories of 
several species, some of which are of economic importance. 
The biologic notes are for the most part incomplete, but they are 
published now as circumstances make it unlikely that I shall 
continue work on the group during the next few years. 
Sub-Order TEREBRANTIA. 
Family Afolothripide. 
Rhipidothrips, Uzel. 
Since describing R. brunneus (‘ Journ. Econ. Biol.,’ Vill, 
1913, p. 216) I have had the opportunity of examining a speci- 
men of R. niveipennis, Reut., from the collection of Reuter. I 
find that it differs in several respects from the published de- 
scription, which necessitates alterations in the key to the genus 
which I gave on p. 218, l. ¢. 
The species can be best separated as follows : 
(a) Cheeks slightly arched, with three or four short, stout, 
forwardly directed spines on the lateral margin of the head 
behind the eyes. Tibie slightly paler near the tip, tarsi pale 
brown. : : ; ; ; brunneus, Williams. 
(b) Cheeks parallel, with no stout spines on lateral margin. 
Tibiz suddenly much lighter near tip (near middle in anterior 
pair). ‘Tarsi pale yellowish. : . neveipennis, Reuter. 
The figure of the antenna of R. niveipennis given by Reuter 
is quite useless. The following are measurements of a specimen 
cope collection kindly lent to me for comparison by Mr. J. D. 
Hood : 
