DEILEPHILA GALlI. 308 



matter, after all, is one that presents little difficulty. I am 

 indebted to Mr. McRae, of Bournemouth, for the following plan, 

 which I have tried ; and as that gentleman kindly gives me per- 

 mission to publish it, I feel I cannot do better than give it in 

 his own words. " Procure," he says, " a large flower-pot saucer, 

 filling it with alternate layers of coarse sand, or gravel, and 

 moss, placing the pup£e on the top, and then covering them with 

 a layer of moss. Saturate the whole with tepid water, and over 

 the whole place a bell-glass. Then place the apparatus in front 

 of the kitchen fire, and inside the fender. Place a few twigs on 

 the top of the outside layer of moss, to enable the insects to 

 crawl up and to dry their wings, otherwise all will be crippled, as 

 the glass is too smooth for climbing. Emergence may be 

 expected to take place in about three weeks. The temperature 

 will often rise to at least 100" F., and, provided the whole is 

 kept sufficiently moist, and shaded from direct radiation by 

 placing a piece of thick brown paper in front of the bell-glass, 

 this heat will not injure the pupte ; on the contrary, it accelerates 

 development. By planting a piece of board behind the incubator 

 to break the draught of cool air from the door, I often had the 

 bell-glass so hot that I could not place my hand against it. The 

 essential principle of forcing or accelerating emergence is heat, 

 and pupse will stand almost any amount provided they are kept 

 moist." "I do not find," continues Mr. McRae, "that the fire 

 going out at night injures the development of the pupse in the 

 least. There is no such thing as a uniform temperature in 

 Nature, and the range between the maximum and minimum in 

 twenty-four hours, at midsummer, is so considerable that I 

 concluded I need not trouble myself about attempting to keep 

 up a regular and fixed temperature." 



This plan has been long known and practised, so Mr. McRae 

 informs me, by the older entomologists, and he adds that it was 

 communicated to him, some twenty years ago, by the late Mr. 

 Edward Newman. 



My captures of D. galii larvae ended last season on the 

 13th of September. Gold and frosty weather set in shortly after, 

 with the result that one of the caterpillars failed to pupate. 

 Still I found myself in possession of twelve healthy-looking 

 pupse. Some of my correspondents began the forcing process 

 immediately after pupation, and, judging from their results, tliey 

 were by far the most successful. I, on the contrary, kept mine 

 simply under cover. They were left in the breeding-cage exactly 

 as they had been formed, — slightly below the surface of the sea- 

 sand, but covered by the usual open-below sandy web or shield, 

 and exposed only to the natural dampness of the sand. 



On January 1st I examined the pupse and found five dead and 

 mouldy, so I at once began the use of the saucer, bell-glass, &c. 



