766 BIONOMICS OF THE BUFFALO-FLY, 



made much headway south of the Roper River, or west of the 

 Daly River. Melville Island, on which Iniffaloes have run since 

 1824, is said to be badly infested; while the adjacent Bathurst 

 Island, which is stocked with goats only, is free. 



Description of Early Stages, Life-History, and Habits. 



The eggs, which are pale reddish-brown in colour, 1 mm. in 

 length, curved on one side and flattened on the other, aie laid 

 singly on their sides on the wet surface of fresh dung, occasion- 

 ally in crevices in dung or in fouled mud an inch or more away 

 from it, and occasionally in fouled mud around buffalo-wallows. 

 Oviposition takes from 2-4 minutes, during which time from 12- 

 20 eggs are laid. The young larva? descend into the dung, where 

 they attain a length of 7*25 mm., and change in colour from 

 nearly white to dirty-white. Under natural conditions, pupation 

 sometimes takes place in the soil under the dung, but usually in 

 the dung itself. In breeding-jars, pupation invariably tt)ok place 

 in the latter situation, whether the dung rested on clean sand or 

 on loamy soil. On two occasions, these flies have been observed 

 depositing eggs on the hair of sweating horses, but it is most 

 improbable that the i-esulting larvfe would i-each maturity. 



In the full-grown larvae, the posterior stigmatic plates, which 

 are situate on the hind margin of the anal segment, are large, 

 blackish, rounded on the outer sides and nearly straight on the 

 adjacent inner margins, with three, irregular, paler spots, and a 

 central opening in each. On the ventral surface of the anal seg- 

 ment, there ai-e several paired tubercles of varying size, surrounded 

 by coarsely granulated skin. The puparium is of the usual 

 Muscid type, 3 mm. in length by l'30mm. in width, barrel- 

 shaped, and reddish-brown in colour. 



Three reared under laboratory-conditions, in March, gave an 

 average of 169 hours for the completion of the life-cycle (192, 

 195, 120 hours). The weather during the shortest period was 

 warm and sultr\', while a good deal of cool weather and rain 

 were experienced during the longer periods. A later rearing 

 (in June), when the weather was often chilly, took 208 hours to 



