244 
Anopheles in Flanders 
tins which had been thrown into it. Ten waters, rendered disturbed or turbid 
through rain, also contained Anopheline larvae. 
The floral and faunal associations of the Anopheline larvae, 
(a) Floral. Out of 106 records the following analysis results: 
Number of times during 
which Anopheline larvae 
Flora were found associated 
G rass ... ... ... ... ... ... ... ... ... 
Grass predominating, with the addition of confervoids and the 
common waterweeds 
Algae—mostly Spirogyra ... 
Algae—with addition of broad-leaved pond-weed ( Potamogeton ), 
water-cress ( Nasturtium ), fringed water-lily ( Limnanthemum ), duck¬ 
weed (Lemna), flag (Iris) 
Water-cress... ... ... ... ... ... ... ... ... 
Water-cress predominating, with addition of other vegetation... 
Sedges ( Carex) and other vegetation 
Confervoids... 
Broad-leaved pond-weed and duckweed 
Rushes (Juncaceae) and algae. Rushes and marestail ( Hippuris ). 
Lily and algae. Fringed water-lily and sedges. Flag. Flag and 
duckweed. Weed unidentified ... 
18(17%) 
17(16%) 
18(17%) 
11 (10-3%) 
6 (5-6 %) 
2 
2 
2 
2 
Each 1 
On six occasions larvae were found in water with no visible foodstuffs. 
Fifteen records are incomplete. Waters in which the visible vegetation was grass 
or algae or predominately either of these gave positive results almost certainly. 
Association with water-cress was not infrequent. In ponds covered entirely 
with a dense mat of duckweed Anophelines have never been found but at 
the margins of certain pools of this character, in open patches of water among 
tall fringing vegetation, the larvae have been taken. The low degree of in¬ 
festation of the ditches of the waterlands is interesting. 
(b) Faunal. The results of 167 records show the following: 
Fauna 
Culicine larvae alone 
Water hog-louse ( Asellus) alone. 
Fresh-water shrimp ( Gammarus ) alone ... 
Culicines and water hog-lice . 
Culicines, water hog-lice and fresh-water shrimps 
Water hog-lice and fresh-water shrimps... 
Number of times during 
which Anopheline larvae 
were found associated 
40 (24 % nearly) 
11(6-5%) 
2 
5 
1 
1 
The number of times during which Anopheline larvae were found alone 
was 109 (65 % approximately). Fresh-water fish of many kinds have also 
been found along with Anophelines. Water-boatmen (Notonecta) have been 
observed, in an aquarium kept at a Casualty Clearing Station, to prey upon 
and suck Anopheline larvae. 
