17 



larval life, as of the egg-stages, varies with the temperature and time 

 of year. The shortest larval period observed has been 14 days in 

 the rains, the longest 48 days. The change to the pupal condition is 

 foreshadowed by a thickening of the thoracic segments, and by the 

 larva seeking a comparatively dry spot. There the last larval skin is 

 shed, the pupa emerging through a slit in the thoracic region, and by 

 its wriggling movements working the skin down to the tail end, where 

 it remains attached to the earth and holding the pupa in place." 



Grassi, who states that the pupce of Ph. papatasii are found in 

 the same localities as the larvae, usually " concealed in cracks in the 

 stones and bricks," sums up his description of the pupal stage as 

 follows : " The pupa is motionless, curved, with a dorsal concavity, 

 yellow, and from 2 to 5 mm. in length ; it is very easily recognisable 

 from the fact that the posterior extremity (last three segments) 

 is enveloped in the wrinkled and brownish larval skin, which serves 

 as a means of attachment. In shape the pupa is cylindriform, 

 with the anterior half swollen, the posterior half attenuated, and 

 the hind margins of the tergites produced into prominent ridges. 

 When examined under a lens it appears bare. The respiratory 

 papillae (tubes) are very small, two anterior and two posterior." 

 Hewlett writes : " The pupa, like the larva, has a very 

 characteristic appearance, . . . Its most distinct feature is 

 perhaps the prominent ridges and projections on the dorsal surface 

 of the thorax. The duration of the pupal stage, like the others, 

 varies according to temperature from 8-9 days in the rains to 

 28 days in December." The same author adds : " The whole 

 period of the life-history from the laying of the egg to the emergence 

 of the fly from the pupa may thus be said to take about one month 

 in the hot weather and two months or more in the cold weather. 

 Observations have however not yet been carried on throughout the 

 whole of the cold weather and the maximum length of life-history 

 is not yet accurately known." 



The bionomics and life-history of Phlebotomus 



Phlebotomus have been dealt with at some length, since it 



as a has recently been discovered that these flies 



disease-carrier. are O f considerable importance as disseminators 



c 



