The Currant Stem Girdi^er. 49 



and deliberately proceeds to girdle it. This is doubtless the most 

 injurious of any of the insect's habits; and yet the manner in 

 which the girdling was accomplished remained a mystery until we 

 had the pleasure of seeing the female cut many shoots in our cages 

 in May, 1896. Most writers have supposed that the girdling was 

 done with the jaws of the insect, but our observations show that 

 it is done entirely with the saw-like ovipositor. 



A female is shown, natural size, in the act of girdling a currant 

 shoot at a, plate IV. She first forces her ovipositor its whole 

 length into the shoot. When she withdraws it, however, shedoes 

 not pull it straight out, but twists it to one side so that it is held 

 at right angles to the body, and then makes it saw its way out. 

 As the ovipositor is curved, its tip first appears through the bark 

 of the shoot ofi" at one side from where it was forced in, and the 

 rest of the " saw " soon comes through leaving a smooth, some- 

 what curved cut forming a part of the circle around the shoot 

 equal in length to about the length of the ovipositor. The 

 enlarged, recently cut shoot shown at b, plate IV, well illustrates 

 the nature of these cuts. Without moving from her position, the 

 female usually again inserts her ovipositor very near where she 

 did the first time, but twists it the other way thus making two 

 cuts extending in opposite directions from one point. She then 

 moves around the shoot until she finds the end of one cut, 

 and proceeds in the same manner to cut another slit. She con- 

 tinues this process of moving around the stem and cutting new 

 slits from the ends of those just made, until the girdle of cuts is 

 complete, or nearly so. We have repeatedly seen a female lay an 

 ^%<g in a minute and in the next four minutes girdle the shoot a 

 short distance above the egg. Sometimes the girdling is so com- 

 plete that the tip falls of at once, but usually a portion of the 

 shoot remains uncut and the tip may remain attached for some- 

 time, especially if the shoot is a large and vigorous one. At b, 

 plate IV, the ends of the girdle did not quite meet ; and in some 

 cases the female lost her bearings to such an extent as to continue 

 the girdle of cuts in a spiral direction so that the last cut was 

 above and nearly an eighth of an inch from the first one. Some- 

 times the female did not first make two cuts from the same point, 

 but at once moved around the stem and made the second cut at 



