ATTACKING THE STEMS. 337 



the centre of the stem, where they burrow up and down, 



feeding on the pith all through tiie summer, enlarging the 



channel as they grow older, until at 



last they have formed a hollow several 



inches in length. When full grown, 



the larva (6, Fig. 350) is whitish and 



fleshy, of a cylindrical form, with 



brown head and legs, and a dark line 



along the middle of its back. Before 



changing to a chrysalis, a passage is 



eaten nearly through the stem, leaving merely the thin outer 



skin unbroken, thus preparing the way for the escape of the 



moth. 



Within this cavity the larva changes to a chrysalis (a. Fig. 

 350, where both larva and chrysalis are shown magnified). 

 Early in June the chrysalis wriggles itself forward, and, push- 

 ing against the thin skin covering its place of retreat, ruptures 

 it, and then partly thrusts itself out of the opening, when in 

 a short time the moth bursts its prison-house and escapes, 

 soon depositing eggs, from which larvae are hatched, which 

 carry on the work of destruction. 



While this insect chiefly infests the red and white currant, 

 it attacks the black currant also, and occasionally the goose- 

 berry. Where the hollow stems do not break off*, indications 

 of the presence of the borers may be found in the sickly look 

 of the leaves and the inferior size of the fruit. 



Remedies. — In the autumn or spring all stems found hollow 

 should be cut out and burnt. During the period when the 

 moths are on the wing they may often be captured and de- 

 stroyed in the cool of the morning, at which time they are 

 comparatively sluggish. 



No. 203. — The American Currant-borer. 



Psenocerus supernotatus (Say). 



This borer is the larva of a beetle, and, although belong- 

 ing to an entirely diff*erent order from No. 202, is very 



22 



