94 Parasitic Arthropoda 
Parasitic Diptera or Flies 
Of the Diptera or two-winged flies, many species occasionally 
attack man. Of these, a few are outstanding pests, many of them 
may also serve to disseminate disease, a phase of our subject which 
will be considered later. We shall now consider the most important 
of the group from the viewpoint of their direct attacks on man. 
Psychodidae or Moth-Flies 
The Psychodidae or Moth-flies, include a few species which attack 
man, and at least one species, Phlebotomus papatasii, is known 
to transmit the so-called “three-day fever” of man. Another species 
is supposed to be the vector of Peruvian verruga. 
The family is made up of small, sometimes very small, nematocer- 
ous Diptera, which are densely covered with hairs, giving them a 
moth-like appearance. The wings are relatively large, oval or 
lanceolate in shape, and when at rest are held in a sloping manner 
over the abdomen, or are held horizontally in such a way as to give 
the insect a triangular outline. Not only is the moth-like appearance 
characteristic, but the venation of the wings (fig. 163, d) is very peculiar 
and, according to Comstock, presents an extremely generalized form. 
All of the longitudinal veins separate near the base of the wing 
except veins R 2 and R 3 and veins Mi and M 2 . Cross veins are 
wanting in most cases. 
Comparatively little is known regarding the life-history and 
habits of the Psychodidae, but one genus, Phlebotomus, contains 
minute, blood-sucking species, commonly known as sand-flies. The 
family is divided into two subfamilies, the Psychodinae and the 
Phlebotominae. The second of these, the Phlebotominae, is of 
interest to us. 
The Phlebotominae — The Phlebotominae differ from the Psychod¬ 
inae in that the radical sector branches well out into the wing rather 
than at the base of the wing. They are usually less hairy than the 
Psychodinae. The ovipositor is hidden and less strongly chitinized. 
The species attacking man belong to the genus Phlebotomus , small 
forms with relatively large, hairy wings which are held upright, 
and with elongate proboscis. The mandibles and maxillae are ser¬ 
rated and fitted for biting. 
According to Miss Summers (1913) there are twenty-nine known 
species of the genus Phlebotomus, five European, eleven Asiatic, 
