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The possibility of their introduction into Britain. 
It has been stated that we may receive in England numbers 
of this Gnat from ships, carrying bananas from the West Indies 
and South America. It is quite possible that some may at any time 
come over in any ships, not only those carrying bananas. It is 
quite possible, if introduced, that they may live for a little while 
in such ports as Bristol, Swansea, etc. It is even possible that 
infected specimens may land, just as they must have done at 
Swansea during the outbreak of yellow fever there. It is extremely 
improbable from what we know of its distribution and its likes and 
dislikes that it could establish itself here and breed. 
All cases so far that I have investigated of Mosquito plagues 
supposed to be due to importation by ships have proved to have 
been caused by one or other of our twenty-two native species of 
Culicide. 
The distribution of Siegomyia fasciala. 
HOWARD, writing on this subject in 1905, says: « We may expect 
to find this species everywhere in the moist tropical zone, or at all 
events, when introduced at any point within the low moist tropics, 
it may be expected to establish itself ». Besides the tropics we 
know it extends well into subtropical even temperate regions. 
The most northernly line seems to run no further than be- 
tween 45° and 44° (at Ravenna, FICALBI) and the most southernly 
the uplands of Victoria, say 38°. 
I do not think its range will be found to extend further north, 
but it may extend further south, down to about 40° to 43° in South 
America. 
Anywhere between these limits we may expect to find in favour- 
able localities this yellow fever carrier, or may expect to have it 
become established if once introduced. 
The localities from which it has so far been recorded are given 
in the following pages. 
