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. i63,d)isverypectdiar 

 and, according to Comstock, presents an extremely generalized form. 

 All of the longitudinal veins separate near the base of the wing 

 except veins R2 and R3 and veins Mi and M2. Cross veins are 

 wanting in most cases. 



Comparatively little is known regarding the life-history and 

 habits of the Psychodidse, but one genus, Phlebotomus, contains 

 minute, blood-sucking species, commonly known as sand-flies. The 

 family is divided into two subfamilies, the Psychodinse 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 

 Psychodinas. 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 (19 13) there are twenty-nine known 

 species of the genus Phlebotomus, five European, eleven Asiatic, 



