SIGNIFICANCE OF STEGOMYIA FASCIATA IN WE8T AFRICA. 247 



and six of them pupated at the end of three weeks, one of which gave rise 

 to a perfectly well-formed female. Unfortunately no details are given as 

 to the temperature in which this experiment was conducted ; but it is 

 important to note that the insects were reared in a greenhouse,, 



Newstead* has conducted similar experiments with eggs of this mosquito 

 from material forwarded from Manaos by Dr. H. Wolferstan Thomas in the 

 year 1906. The eggs were laid on moist white filter-paper ; these were 

 dried in the air and subsequently placed in a desiccator with chloride of 

 calcium for 24 hours, and finally transmitted to England in glass tubes, 

 tightly corked. The following data indicate the results of this experiment : — 



September 9-11. ^gg^ hiid at Manaos, Amazon. 



October 26. Eggs reached England. Placed in water at a tempe- 



rature of 23° C.'(= 73-4° F.). 

 „ 27. 12 larvse hatched during the previous night and one 



after twelve hours immersion. 

 ,, 28. Larvae began moulting: 



„ 30. All larvse completed first moult. 



November 4. Larvse pupated. 



„ 7. First imago, a male, hatched. This example lived for 



6 days. 

 „ 8. A male and female hatched. 



The breeding-jar was kept in an incubator at an even temperature of 23° C. 

 For the greater part of the time the insects were in complete darkness ; but 

 a little light was admitted occasionally during the day. 



Summari/. 

 Eggs remained dormant and practically dry 45-47 days. 



Life-c^de. 



Eggs. Incubation period 6-12 hours. 



Larval stage 9 days. 



Pupal stage 3 days. 



Complete cycle 12-13 days. 



From these data it will be seen that the life-cycle was completed as 

 rapidly as the minimum period given by Goeldi t in his classical memoir on 

 the Mosquitos of Para. This is all the more remarkable seeing that the larva3 

 and pupse were kept in almost total darkness and also in a highly vitiated 

 atmosphere. Subsequent experiments have proved, however, that eggs kept 



* Journ. Trop. Med. & Parasitology, Liverpool, vt>l. iv. p. 143. 

 t ' Os Mosquitos no Para,' p. 6. 



