184 MEDICAL ENTOMOLOGY 



Cruz Institute, have described the South American species of the genus 

 Phhbotomus ; most of them were taken in uninhabited regions, particu- 

 larly in forests where bamboo-inhabiting mosquitoes were plentiful. 

 For the determination of the species they note that the relative lengths 

 of the segments of the palpi afford valuable taxonomic characters in both 

 sexes. They give the following key to three species : 



1. Scales absent on the abdomen ......... 2 



Scales present on the abdomen between the hairs . . . squatniventris. 



2. Last palpal joint longer than the others .... longipalpis. 

 Last palpal joint shorter than the second or third . . . intermedium. 



Phlebotoinns rostrans, Summers. This species is distinguished from 

 the above by the great length of its head and proboscis, which in the 

 female, taken together, are half the length of the rest of the body. It is 

 recorded from Rio J a vary. 



The bite of the sand fly is well known to everybody who has 

 experienced it ; the stealthy way in which it enters a mosquito net, 



either through the meshes, or by crawling under the 

 Bionomics 



curtain, or even by passing in between the mattress and 



the framework of the bed, make it a hated pest. The intolerable 

 itching produced by the bite, and the stinging nature of the bite it- 

 self, are diagnostic of the presence of these flies. Some people, how- 

 ever, are in no way affected by it. The hands, the wrists, the 

 dorsum of the feet, and the ankles are the favourite sites in which they 

 bite ; the face is also sometimes attacked. If a light is kept close to 

 the bed fewer will enter the net. 



According to Marett, Phhbotomus in Malta does not fly long distances, 

 about twenty yards being the limit of range of flight. If a strong 

 wind is blowing they are only seen in very small numbers, but when the 

 wind dies down they reappear and their presence becomes very noticeable. 

 During the daytime they are to be found in dark corners, among 

 dark clothes, recesses in cupboards, behind pictures and similar places. 

 The dark bathrooms of Indian houses are favourite resting places, where 

 they will bite even in the middle of the day. 



In Malta Newstead notes that certain places were heavily infected 

 while in others hardly any flies could be found ; the same has been 

 observed in Madras, for some houses have large numbers, while others 

 close by are entirely free. Newstead attributes this localization to some 

 unknown conditions which favour the breeding of the flies. 



In Malta Marett has found the flies resting in caves and embankments, 

 and in cracks in walls where the surface pointing has fallen away, 



