52 Bulletin 126. 



lower end of its burrow for the distance of about three-fourths of 

 an inch, and also eats a passage way through the woody portion 

 of the stem out to the outer layer of bark which soon dies and 

 sinks in slightly at this point. This passage way is partly filled 

 with excrement or "frass," and the grub then proceeds to spin a 

 thin silken cocoon about itself within which it remains as a grub 

 all winter. These winter preparations are well illustrated at b, in 

 figure 18. Sometimes the small dead sunken area of bark cover- 

 ing the passage to the cocoon may be readily detected in winter 

 or spring on an injured shoot. This passage-way enables the 

 adult insect (the saw-fly), to easily make its way out from the 

 cocoon in May. 



Natural Enemies. 



The eggs embedded in the pith of the shoots, and the borers as 



they tunnel their way down the pith, seem to be beyond the reach 



of their enemies. But the necessity of eating a passage-way to 



the outer bark to provide for the emergence of the adult insec't 



affords an opportunity which their little foes seem on the alert to 



secure. Nearly one-third of the full grown borers sent us in the 



spring of 1896, had been attacked and killed bj^ tiny hymenopter- 



ous parasites, evidently after they had spun their cocoons. In 



every case the little foes had doubtless broken through the thin 



door opening into the passage-way leading to the cocoon, and had 



inserted their eggs into the body of their helpless victims. These 



eggs hatched out maggots which lived at the expense of the body 



of their host. When full grown the little maggots spun their 



silken cocoons within the larger cocoon made by the borer. In 



one case five of the tiny Braconid parasites {Bracon apicatus Prov.) 



emerged from one cocoon of the currant stem-girdler. Curiously 



enough the parasite nearest the passage-way emerged first, and 



the others followed in regular succession ; we saw one emerge, 



and upon examining the cocoon next behind, found the adult 



parasite all ready to appear, while in the next cocoon, we found 



the insect still in the pupa state. It is to be hoped that this little 



enemy will continue its good work among the grubs of this new 



currant pest. 



How TO Control the Insect. 



The currant-stem girdler can not be reached at any time or in 

 any stage with a spray. Fortunately, however, its habits are 



