July, 1914.] THE APPLE MAGGOT. 61 



after deposition and were placed in apple pulp, in a hollow glass 

 slide in a moist chamber; it is possible, therefore, that the normal 

 period was somewhat shortened. 



The mortality of the egg, in our investigations, was noted in 

 conjunction with that of the larva. The varying percentages of 

 mortality of these two combined will be found discussed in some 

 detail under observations on the larval stage. 



Ross (55), by examination of a large number of egg punctures, 

 found an average percentage of dead eggs, including infertile 

 eggs, ranging from 17.1 per cent to 34.9 per cent. 



THE LARVA. 



On hatching from the egg the larva immediately begins to 

 penetrate the pulp of the fruit, following no direct course, but 

 wandering about in every direction, sometimes working just 

 beneath the skin or again penetrating to the neighborhood of the 

 core. At first the tunnel is very small and not easily made out. 

 Later, if the condition of the pulp is favorable to the development 

 of the larva, the tunnel walls turn brown and are conspicuous. 

 When several larvse are present in a single fruit of mellow pulp the 

 tunnels may coalesce, and the greater part of the fruit may be 

 broken down, although the apple may show, on the outside, 

 comparatively little sign of its condition. 



When apples of hard pulp are attacked, such as many winter 

 varieties, either the larva develops very slowly on hatching, or 

 within a short time development ceases entirely and the larva 

 may die. If such fruit chances to fall early, and if it grows 

 mellow before cold weather arrives, development of the larva 

 may then pass on rapidly to maturity. 



Immediately on completing its growth the larva leaves the 

 apple in order to enter the ground for pupation. A certain 

 mellowness of the pulp is necessary in order that the larva may 

 mature. This condition is not fully reached, under normal 

 conditions, until the fruit has fallen from the tree. The exit of 

 the larva therefore, does not normally take place until a longer 

 or shorter period after the fall of the apple. 



. PERIOD BETWEEN FALL OF APPLE AND EXIT OF LAR\M. 



The length of the period between the dropping of the fruit and 

 the exit of the larvae is a matter of much concern, economically, 



