Observations on the Subgenus Fhalangomyia of the Genus Culex in Ecuador with 
Description of a New Species (Diptera: Culicidae) 
Roberto Levi-Castillo^ 
The subgenus Fhalangomyia has rather gen- 
erally been considered as a synonym of the 
subgenus Culex although, especially in the 
species found in Ecuador and described here- 
in, it has characters which differentiate it very 
clearly. The terminalia are very characteristic. 
The strongly chitinized structure of the clasp- 
er and the presence of strong hairs on its 
outer surface constitute a great difference 
from the condition found in members of the 
subgenus Culex. Fhalangomyia seems to repre- 
sent one of the oldest branches of the genus 
Culex, as indicated by its adaptation to a high- 
altitude environment. 
All the members of this subgenus are found 
only in the Andean countries of South Ameri- 
ca. They are large mosquitoes with very well- 
developed bodies and strong, long legs. They 
are adapted for high-altitude flying and for 
low oxygen consumption and, therefore, are 
always found at altitudes of more than 2,000 
meters above sea level, where no other mos- 
' quitoes and few other insects of any sort can 
live. One of the two species considered here 
was found at an altitude of 2,900 meters near 
the city of Quito and the other near the town 
of Cuenca at an altitude of 2,500 meters. In 
the Andean region of Ecuador the median 
temperature is ordinarily between 14.5° and 
20°C. (58°— 68°F.), and wind velocities of 5 to 
25 miles per hour prevail. Thus, in order to 
live, mosquitoes must be adapted to this en- 
vironment. 
^ Director, Ecuadorian Center for Entomological Re- 
search, Guayaquil, Ecuador. Manuscript received April 
14 , 1952 . 
The most interesting characteristic of these 
mosquitoes is the fact that larvae, pupae, or 
adults die very shortly if they are taken to sea 
level, apparently because their metabolism has 
been adapted to the oxygen shortage of the 
high altitudes of the Andes. Thus the author 
was unable to breed larvae of Fhalangomyia at 
sea level, even when water from the breeding 
places, with all the algae present, was brought 
to the laboratory. Apparently, then, compres- 
sion is a main factor in killing the larvae, 
although they sometimes survive 10 to 12 
hours of being at sea level. Also temperature 
changes will kill the larvae, and at sea level 
both the temperature and humidity are higher 
than those at over 2,000 meters above sea 
level. However, even placing the larvae 
brought to sea level in refrigerators held at 
the same temperatures as the highlands does 
not prevent their dying in a few hours. This 
proves that the subgenus Fhalangomyia is only 
adapted to live at high altitudes, in the An- 
dean region of Ecuador. The problem of the 
effects of oxygen, basal metabolism, and en- 
vironment on highland mosquitoes has not 
been studied sufficiently, and it is one of the 
research projects of the Ecuadorian Center for 
Entomological Research. 
Two species of Fhalangomyia have been 
taken in the highlands of Ecuador, one pre- 
viously known and one new to science. They 
are both described here. 
Culex (Fhalangomyia) archegus 
Dyar, 1929 
LARVA (Fig. \a, h)\ Head rounded, wider 
than long. Antennae long, tapering, with a sub- 
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