58 Bulletin 126. 



the very tip of the shoot in the crotch formed by the bases of the 

 tip leaves; at c, plate V, is shown one of the eggs much enlarged, 

 and at d, are represented three eggs, natural size, in the position 

 in which they were laid. As the fly is smaller than a house-fly, 

 these eggs are comparatively large ones for such an insect, and 

 would thus indicate that one female fly does not lay a large num- 

 ber of eggs. How soon the eggs hatch, we did not determine ; 

 it is doubtless but a few days. 



Work of the maggot. — The little white maggot which emerges 

 from the &ggy crawls down the shoot for a short distance (less than 

 an inch), and then burrows its way into the pith of the shoot. 

 The entrance hole of the maggot is usuall)^ quite conspicuous, as 

 the surrounding tissues turn blackish. After the maggot reaches 

 the pith it proceeds to tunnel its way downward, making a small, 

 somewhat tortuous tunnel in the pith. After tunneling about 

 half the length of the shoot (sometimes this is six inches or more 

 but may be only an inch or two), the maggot works its way 

 nearly out to the bark, and deftly continues its tunnel around the 

 shoot, thus girdling it from the inside ; this interior girdle or tun- 

 nel shows well in the broken shoots at b, plate V. Usually the 

 maggot eats a small hole out through the bark, at some point in 

 the girdle ; the use of this opening, we have not determined. 

 The maggot continues feeding on the pith £X the point where the 

 girdling was done, and nearly severs the shoot in this way. The 

 shoot in the lower right-hand corner of (5, plate V,is represented with 

 the bark removed to give a clearer idea of this interior girdling. 

 Usually the maggot girdles the shoot in a spiral manner, some- 

 times tunneling nearly twice around, as shown on one shoot in 

 the right-hand corner of b, plate V. 



The part of the shoot above the girdle soon wilts, shrinks in 

 size and droops over as is shown in figures 20 and 21. Soon 

 after the tip droops, a dry rot begins at the girdled point, the 

 wilted portion turns a dark blue color, and the whole shoot usually 

 dries up and dies. Perhaps the maggot could not develop in a 

 growing shoot, and it would also be hindered in its transformation 

 to the adult in such a shoot. This may be the explanation why 

 the insect girdles the shoot. 



