30 
ably due to hold-over cases, which reappeared as the weather warmed up 
in spring. 
50 
t 
45 
40 
35 
30 
25 
20 
15 
10 
+4 
May June July Aug. Sept. Oot. Nov- 
Number of cases of malaria (upper line), and abun- 
dance of Anopheline mosquitoes (lower line). 
Species oF Mosguirors at Herrin, 1920 
The following table gives the species of mosquitoes reared from col- 
lections at Herrin, the months when collected, and the numbers of the 
breeding places in which they were found. For example, the first species 
listed (Anopheles guttulatus) was bred from larvae or pupae collected 
in August from breeding places Nos. 4 and 5, in September from Nos. 4 
and 7, and in October from Nos. 5 and 6. 
Of these eleven species, three are worthy of special notice, namely, 
Anopheles crucians, Aédes sollicitans, and Culex degustator. The first 
two are distinctly salt-marsh species, very rarely found more than fifty 
miles from salt water. Dr. Harrison G. Dyar, who confirmed the determi- 
nations of these species, expressed great surprise that they were found 
