The mosquitoes of the island of Corfu Greece.

THE MOSQUITOS OF THE ISLAND OF CORFU, GREECE.
By Dr. THEODORE
STEPHANIDES.
The following mosquitos have been observed by myself in the Island of Corfu
in tile course of a five year study durin, u which more than 350 bodies of water, ranging
from pools to small lakes, were examined.
1, Anopheles maculipennis, Meigen.
The larvae are found in the low-lying districts of the Island in shallow pools and
irrigation ditches containing a medium amount of aquatic vegetation yet well
c,IjOsed to sunlight. They are sometimes present along the edges and in the back-
,v;lters of drainage canals with an appreciable current, and frequently in slightly
i,rnckish (up to 10 per cent. salinity) waters by the sea-shore. They are most plentiful
irl Lake Antiniotissa among the floating masses of Monostromn (? b~dlostcm, .Roth-
\\‘ittr.) at the mouths of several fresh-water springs which flow into that shallow and
sliglltly brackish mere from the south.
The adult bites most frequently after sunset and is the principal transmitter of
t\lc malarial parasite in the Island.
2. Anopheles bifurcatus, Linnaeus.
This is the commonest Corfu A~zo~heZes. The larvae are present throughout the
~‘car, often in considerable numbers, in cool, shady ditches, springs and rills with a
slight current and plenty of aquatic vegetation.
Though plentiful, A. bifurcatus is not of much epidemiological importance, so
far as the climate of Greece is concerned, as the adults appear too late in the year to
constitute a serious menace.
3. Anopheles (Mysomyia) superpictus, Grassi.
The larvae are met with, sometimes in great abundance, in small pools in the stoq
and pebbly beds of mountain rills where the water is warm and unshaded. In some
of its habitats very little macroscopic aquatic vegetation was present, in others there
ivere masses of Clndo@~orn sp., but only on the bottom, leaving a layer of clear
water on the top.
A tiny mountain spring near the village of Iiouloura was particularly instructive
3s to the bionomics of both A. sz~~~~~icfz~s and A. bifurcatt~s. This spring formed two
small pools, heavily shaded by bushes, which until last year contained great numbers
of larvae of A. biftzrcntzls and only an occasional A. sz+@‘ctus. Last summer the
bushes had been cut by peasants for fire wood, and the pools now received the full
force of the sun. This time I found them swarming with A. sz@~Qktus larvae, not
one of A. bifzucatus being present. In view of the relative inocuousness of
A. bifwcatw it is feasible that the presence of brushwood along mountain streams
may sometimes be of importance in malaria prevention.
The adult seems to bite more freely during the day than A. nzacdipewis.
4. Culex pipiens, Linnaeus.
The commonest Corfu mosquito. The larvae are found in all bodies of water of
not too great a size. They thrive both in open and in weedy pools, in the purest
and in the most contaminated water. I have even discovered them in the oily and
almost ink-coloured rain-water collected in disused olive-oil barrels. Their favourite
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406 DR. THEODORE STEPHAXIDES.
habitat however seems to be shallow ditches with a mud bottom and little vegetation
The Corfu larvae resemble those described by Capt. Barraud from Mesopotamia, a; *E
they generally have a very long siphonal index (5 to 6.5) and 15 to 17 pecten teeth. :*
The adult is the mosquito most often met with in human habitations ; it bites
more freely by night.
’ 5. Culex laticinctus, Edwards.
Much rarer than C. @j%ens, but the larvae sometimes occur in swarms in ’
ornamental basins, troughs and pools with clear water.
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’ 6. Culex univittatus, Theobald ($erexig~s, Theobald).
Comparatively rare. The larvae, however, may sometimes be met with in fair
numbers during the early summer amon g the aquatic vegetation along the margins
of the larger ponds.
7. Culex tipuliformis, Theobald.
Apparently very rare, as I have only once (17.xii.35) observed a. few larvae in ;l
shallow weedy pool.
8. Culex (Neoculex) apicalis, Adams.
A common Corfu species. The larvae are found throughout the year in pools
and ditches, especially those with copious aquatic vegetation. Sometimes in very
slightly brackish (about 1 per cent.) water.
9. Culex (N.) hortensis, Ficalbi.
Found in the same habitats as the above but less plentiful. The adult can only
be distinguished from that of C. apicalis after careful examination, but the larvae
can be separated at the first glance. Those of C. hortemis have very long siphonal
tufts (3 to 5 times the diameter of the siphon), whilst the tufts of C. a$icnZis arc
never longer than the siphonal diameter and sometimes completely lacking.
10. Culex (Barraudius) modestus, Ficalbi.
Very rare. So far I have only found (16.viii.34) two larvae in a water-butt among
swarms of larvae of C. pipielzs.
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11. Theobaldia annulata, Schrank.
Very common. Larvae usually in shallow but fairly clear ditches, occasionally
in wells. Gregarious with T. Zotzgenveohtn and C. PipZ’e~zs throughout the year.
The adult does not often enter habitations but bites freely in the open, both in
the day and at dusk.
‘\’ 12. Theobaldia longeareolata, &Iacquart.
Qne of the commonest Corfu mosquitos. The larvae are observed throughout
the year often in swarms, in shallow but clear ditches ; also in Lvater-butts, tanks and
wells. They are extremely voracious and will attack the larvae of other mosquitos
and even their own kind. The 3rd stage larvae are apparently the most predacious
and will kill 4th stage larvae much larger than themselves. The nymphs are both
light and dark coloured, the latter being slightly the smaller. The light-coloured
nymphs produce female mosquitos and the dark males.
The adult is the largest Corfu mosquito, attaining a length of 8 mm. Its habits
are the same as those of T. nwztlntn.

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THE MOSQUITOS OF THE ISLASD OF CORFV:, GREECE.
407
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13. AGdes (St egomyia) fasciatus, Fabricius.
Extremely plentiful. The larvae are found in all except very foul waters. They
are often abundant inside houses in water-tanks, cisterns and e\-en in flower-vases
;u that may have been overlooked for a few days.
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The adult is, with C. @piens, the mosquito most often met with in habitations.
It bites more frequently during the day and can be recognised, even before being
seen, by its peculiar high-pitched piping.
14. ABdes (Finlaya) geniculatus, Olivier.
Very rare. Two larvae only discovered (17.iii.35 and 24.xi.35) in a rain-waterfilled
hole in the trunk of an elm tree.
15. AEdes (F.) echinus, Edwards.
Fairly common. I have often found the larvae in holes in elm and olive trees
containing rain-water.
16. Aiides (Ochlerotatus) zammittii, Theobald.
Common on the sea-coast where the shores are rocky, as the larvae ai-e found
in rock-pools contain’ing sea-water. This water is often so salt from evaporation that
brine-crystals have begun to be deposited and, in most cases, contains no other
forms of animal life except a tiny Coleopterous beetle, Ochthebim sp.
The adult does not often enter habitations,
both in daylight and at dusk.
17. ABdes (0.) detritus, Haliday.
but it bites freely on the sea-shore
Extremely abundant. Their larvae are met with in countless swarms (autumn,
winter, spring) in pools, ditches and swamps of slightly brackish (2 to 4 per cent.)
water by the sea-shore. Occasionally in quite fresh water with C. pipims larvae.
The adults are not often. found in habitations, nor do they seem to be very
troublesome-taking their huge numbers into consideration-in the open.
18. Uranotaenia unguiculata, Edwards.
A rare mosquito whose larvae I have only found during the summer months,
in a shallow and weedy ditch kept always full by water dripping from a moist clay
bank.
Mosquito larvae are exceedingly scarce (so far as Corfu is concerned) in large,
open, deep and permanent bodies of water. They are plentiful on the other hand in
small and temporary collections or on the margins of large but shallow bodies of water
and, for some species, in bays and pools along the course of slow-running streams.
The principal reason for this state of affairs is that mosquito larvae, with their
short life-cycle, can develop in temporary bodies of water which are uninhabitable
to their chief enemies, the larvae of the Coleoptera and Odonata, whose life-cycle
requires as much as five years in some species.
* Consequently the greatest prudence and circumspection should be exercised
when draining bodies of water or treating them with larvicidal substances fatal
i ; also to the above-mentioned insect larvae. For, should the large bodies of water
alone be attended to and the smaller ones overlooked or neglected, there is grave
danger of destroying the breeding-grounds of the mosquitos’ enemies rather than those
of the mosquitos themselves and thus intensifying instead of abating the mosquito
k
menace.
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