240 
Anopheles in Flanders 
In the large district the following results were obtained. At Moulle three 
extensive sheets of water were examined. One, a large lake near the chateau, 
had a great deal of marginal duckweed and algae while the central water 
was more open but supported large floating mats of algae. The Anopheline 
larvae were of all sizes, extremely numerous and could readily be seen dotting 
the surface of the water. This is one of the two waters which have been dis¬ 
covered to be highly infested and by reason of this and their large extent constitute 
real menaces. Another small lake near by and of similar character, in spite 
of repeated search, yielded very few larvae, while a third gave a negative 
result. At Bleue Maison a few Anopheline larvae were found in a ditch over¬ 
grown with vegetation consisting mostly of fringed water-lily and tall sedges. 
At Watten two long ditches, each about 300 yards in length, and charac¬ 
teristic of the district, were examined intensively. They were mostly covered 
with duckweed, fringed with high rushes and had occasional open patches of 
water. No Anophelines were found. Another ditch running by the western 
side of the Watten—St Omer road, was also examined in detail. It was 
choked with high rushes and grasses and the surface was covered in many 
places with fringed water-lily and duckweed. The result was negative. The 
main canal was fringed in places with duckweed and grasses and stranded 
stalks of various plants but the results of many examinations were also 
negative. On the outskirts of St Momelin a small pool was discovered slightly 
infested. At Moulle, where the highly infested lake was situated, there was 
a dysentery camp for Chinese and a large Casualty Clearing Station—a 
dangerous association. 
Twelve waters which included pools and ditches in the Wylder—Rexpoede 
district gave a negative result. 
Armentieres District. This district is of interest as showing, in contrast 
with most of the areas surveyed, the Anopheline conditions existing near a 
large town. In extent it is about 3 square miles and lies between Armentieres 
and its outlying suburb Nieppe. About two-thirds is open, low-lying farming 
country. The examination was made in the summers of 1915 and 1916 and 
in the town showed negative results with regard to the infestation of re¬ 
ceptacles such as water butts, ornamental pools and reservoirs. The canal 
also was negative. On the northern outskirts near the canal was a patch of 
low-lying, grassy, water-logged land which yielded numerous larvae. From 
the south-eastern suburb, Chapelle d’Armentieres, one specimen of A. maculi- 
jpennis, female, was brought to the writer. A mile to the east of the town 
a small Anopheline pool was discovered but no record of its degree of infesta¬ 
tion has been retained. 
Isolated Districts. The results obtained in the isolated districts examined 
may be given conveniently in tabular form. 
