BREEDING PLACES 59 



green growth had only just reached the condition deemed 

 suitable by the fly as cover for the pupae. An opposite 

 condition was found on Bulago. A tree had large horizon- 

 tal branches near the surface of the sand arching over 

 which was a canopy of half dead creeper, throwing very 

 poor shade, but with some fresh green shoots springing 

 out so that in a very little while it would form a good 

 shelter. Forty-five pupae were found here, of which 

 twenty-seven were dead ; in three the adult fly was almost 

 ready to hatch, and the other fifteen were in the earliest 

 stage of development. 



These facts show that the herbage had been at one 

 time dense enough to throw good shade, but having died, 

 many pupae beneath it had been killed by exposure to 

 the sun's heat. Now that fresh green shoots were growing 

 again, the fly considered the shelter good enough, and had 

 begun to use the spot again as a nursery. 



At another time a boy searched for pupae at the base 

 of a papilionaceous tree, which having thin foliage throws 

 poor shade, and in this case had recently died. Here 

 were found 130 shells from which the adult fly had emerged, 

 and five pupae, all dead. Owing to the death of the tree, 

 and the poor condition of rambling plants around its 

 base which had at one time thrown good shade, the fly 

 no longer considered the spot a suitable one, and all the 

 pupae that had been deposited there when the shade was 

 good had either hatched out or died. 



Lastly, among the requirements of the pupae is proximity 

 to water. The pupa seems to require this, although its 

 actual surroundings must be dry. Now, inasmuch as 

 the optimum conditions of boil and shade are provided 

 by the raised beaches of sand or gravel that have been 

 left by the subsidence of the lake from a former higher 

 level, these raised beaches being naturally near the water 

 it might be argued that the pupae were found here not 

 because the beaches were near the water, but because on 



