162 



cent, respectively in from one to four days. Dry and humid conditions 

 are therefore direct factors in induciiig the immediate or deferred 

 hatching of eggs. Eggs stored under dry conditions yielded larvae after 

 262 days, when immersed in water. Incubated eggs were exposed to 

 varying temperatures to determine the effect on hatching. Exposure 

 was continued for 21 hours and the eggs were then placed in water at 

 75° F. and examined after 128 hours. Exposure to 29° F. gave 81 per 

 cent, hatching ; to 75° F., 80 per cent. ; to 95° F., 28 per cent. ; and to 

 102° F., 12 per cent. No hatching occurred after exposure to a tem- 

 perature of 107-6° F. for 24 hours. Heating to 114*8° F. for 30 

 minutes destroyed the vitality of eggs which had been laid for 15 or 16 

 hours ; similar eggs heated to 97° F. hatched normally. The onlv 

 enemy definitely known to attack the eggs of S. fasciata under storage 

 conditions was a species of Psocid. 



Larvae developed readily in water containing a plentiful supplv of 

 organic matter, such as dead leaves, boiled white of Qg^g^ rice, dead 

 insects, etc. The first moult was not passed through in tap water, 

 until organic matter was added. Scarcity of food produced a high 

 mortality and, among living individuals, increased the duration of this 

 stage in some cases to 70 days. Under favourable conditions larval 

 development was completed in four days, and adult males appeared 

 on the fifth day. Bacteria were probably assimilated by the larvae 

 and may possibly have been essential to development. Both larvae 

 and pupae were unable to withstand complete submergence for 20 

 hours. Activity was maintained during exposure to the heat of the 

 sun, when the temperature of the water varied from 75° F. to 103° F. 

 Water heated to 115° F., however, proved fatal to both larvae and 

 pupae. Exposure to a temperature of about 40° F. for two or three 

 hours caused larvae and pupae to become dormant, the former being 

 found on the bottom of the containing vessel, the latter remaining on 

 the surface. Pupae resumed their activity at 60° F., and larvae at 

 80° F. No cannibalism Avas observed among the larvae, although the 

 decaying bodies of those which died in the breeding jars served as food 

 for the survivors. 



Pairing and feeding on the part of adult females was found to occur 

 as soon after emergence as possible. Dry weather acted as a deterrent 

 to feeding both in and out of doors ; drought probably caused an 

 absence of odour and a consequent failure to recognise the presence 

 of a host. Fertile eggs were deposited after the first blood meal, but 

 only when water or moist surfaces were available. Vigorous females 

 fed within 24 hours after egg-laying and again on the following day. 

 Goats, dogs, bandicoots and rats proved suitable hosts. In two cases 

 single eggs were laid by females which had been fed on a mixture of 

 blood and honey, and blood and syrup, respectively. The duration of 

 the adult stage without food averaged from six to eight days, with an 

 extreme of 12 days. Moist conditions were more favourable for 

 prolonging this stage than drpiess or blood meals. When water was 

 not available for oviposition, the average duration of the adult female 

 stage was prolonged to 31*3 days, with an extreme of 74 days. Experi- 

 ments to induce oviposition in the absence of a blood meal met with 

 negative results. In one case, a female which had survived on honey 

 and white of egg for 56 days without egg-laying was given three blood 

 meals ; fertile eggs were deposited four days after the first blood meal. 



