96 TEANSACTIONS OF THE ILLINOIS 



like the blow-flj maggot. The apple worm mines the apple especially 

 about the core; the apple maggot burrows the flesh, hollowing out 

 irregular cavities about the size of a pea, and where there are several 

 of the maggots in an apple at once, these may run together, reduc- 

 ing the greater part of the pulp to a filthy mass. 



Has this insect been overlooked by our orchardists, or is there 

 some mysterious barrier of habit or environment which prevents it 

 from entering the apple orchard in this region and restricts it to its 

 native food? This question is especially important to orchardists, be- 

 cause this insect is not amenable to the treatment which we have 

 lately found so efficient against the codling moth. The small, two- 

 winged fly, the adult of the apple maggot, lays its eggs, like the 

 codling moth, in the blossom end of the apple, and from this point 

 the young larva penetrates the apple much as does the apple worm; 

 but this attack is not made until September, and does most damage 

 to the early apples — a season far too late to permit the application 

 of arsenical poisons to the fruit. Will you look at your wormy ap- 

 ples this winter, and watch your fruit next fall, and let us know 

 what you find? 



Then what do you know about the plum curculio in the apple? 

 That it deposits its eggs there, and that these may produce an active 

 and voracious larva, some of you know full well. That these larvae 

 may mature in the apple and give origin to the adult curculio, I have 

 proved repeatedly by breeding it as Walsh did long before me — a 

 fact stated in one of your previous reports; but what percentage of 

 these plum curculios really come to maturity in the apple? If not 

 at least two or three per cent, then this fruit is unfavorable to their 

 development, and any invasion of the apple orchard by them must 

 soon run out, doing only temporary mischief. This is a thing that 

 a number of ordinary observers can help to determine readily and 

 easily, while a single one or two would find it a very formidable task. 

 To eliminate most of the chances of local or temporary influence, 

 will not each of you lend me for a year or two, as you notice the 

 crescent mark and dot of this well-known insect upon your apples, a 

 bushel or more of this speckled fruit? I will then undertake to put 

 it in the best condition possible to breed the beetle, and report to 

 you precisely the result as to the number of infested apples which 

 finally yield the matured insect. This also is a species apparently 

 little affected by such applications of arsenic as we dare make to 

 the apple then, and we need all the more to know the whole truth 

 about it. 



Further, there is the question raised by Mr. Weir's observations 

 on the plum curculio in our native plums. As they stand, these ob- 

 servations prove too much, for if only one in thirty-five hundred 

 eggs mature the beetle in the native plum, the curculio could not 

 possibly have maintained itself here under primitive conditions, the 

 female laying at most only about a hundred eggs a year. We must 



