27 
_ANOPHELINE CULICINE 
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A mere glance at the table (p. 28) or the diagram will show that 
there is a great difference in the breeding places in respect to their pro- 
duction of mosquitoes during the season. It is very evident that an 
abundance of Anopheline mosquitoes may be produced in a place in which 
few Culicine species are bred, and vice versa. It may be difficult to ac- 
count for these variations in tiie numbers of mosquitoes produced in 
different situations, but a study of conditions at Herrin may help to dis- 
tinguish the types of places that are most dangerous. 
COMPARISON OF BREEDING PLACES 
No. 1, an open ditch, proved to be of little importance for the pro- 
duction of malarial mosquitoes, but of considerable importance for the 
other type. In the main channels of this ditch the waste water from the 
mines seemed to prevent mosquito development, and (a very important 
fact) the edges of the ditch were clean, with little or no overhanging 
vegetation to furnish protection to the mosquito larvae. Those found 
were in the small fecders or tributaries; and in most cases contamination 
of the water in them by the filth of the street made conditions unfavor- 
able for Anopheles larvae. 
No. 2, a series of sink-holes, produced relatively few mosquitoes, 
either Anopheline or Culicine. Many of the pools dried up wholly or 
partially, the receding waters leaving edges exposed and unprotected, so 
that predaceous enemies could keep the mosquito larvae and pupae down 
io a minimum. 
Nos. 3, 4, 5, and 7 all contained considerable water, had much grass 
or weeds along their margins, and appeared to contain enough suitable 
food for the development of malarial mosquitoes. No. 3 is an especially 
typical breeding place for them. 
No. 6 did not seem to be favorable to the production of Anopheline 
mosquitoes. None of either kind were found in Part B, which contained 
much waste water from the mines, and but a few in Part A, which from 
its character might be expected to contain Anopheles larvae. 
No. 8, including all sorts of domestic containers of water, produced 
no Anopheline mosquitoes whatever, but was responsible for some Culi- 
