﻿6 NINTH ANNUAL REPORT 



that where the foliage was insufficient they would finish up on the 

 fruit. Quite frequently, since then, I have in my travels found the 

 gooseberry bushes in the eastern counties of the State defoliated by 

 this pest; but it is seldom complained of in the western counties, and 

 Mr. Walsh, in the course of twelve years collecting, met with but a soli- 

 tary specimen of the moth, near Kock Island, Illinois, although the 

 wild gooseberry was abundant in the woods in that locality. 



IT PREFERS THE GOOSEBERRY TO THE CURRANT. 



This insect shows a decided preference for the Gooseberry, always 

 attacking that plant first when growing side by side with currant 

 bushes. Hence, and because it is generally preferable to apply the 

 popular name of an injurious insect to the state in which it commits 

 its depredations, I have given it the distinguishing term of " Goose- 

 berry Span-worm," though Fitch originally called it the American 

 Currant Moth. The term " Currant Geometer or Measuring Worm " 

 has subsequently been used without any particular reason. 



THE MOTH IS CLOSELY IMITATED. 



There is another moth common in Missouri and in most parts of 

 the country, which in flight and general appearance bears so close a 

 resemblance to the parent of our Gooseberry Span-worm that the 

 two at first sight are easily confounded, and furnish a remarkable 

 illustration of the fact that insects differing widely in structural details 

 often have stamped upon them the same general appearance, where 

 what naturalists understand as "mimicry" could apparently have 

 had nothing to do in bringing about the resemblance. I refer to a 

 little moth often seen fluttering about the Fragrant Sumach (/i'Aws 

 aromatica) on which its larva perhaps feeds. It has precisely the 

 same color and very much the same markings and differs from the 

 Gooseberry moth only in details of venation, in the simple feelers in 

 both sexes and in the somewhat smaller size, more rounded and more 

 diaphanous wings. It has been referred to an entirely different 

 Family (.5<9m5^/6'^(fcB), but evidently belongs to the Geometers. 



PARASITES . 



No parasite has been mentioned by previous writers as attacking 

 the Gooseberry Span-worm, but I have reared an undescribed Tachina- 

 fly from its pupa. 



REMEDIES. 



Many different applications have been used to kill this worm. A 

 correspondent of the Country Gentleman (June 17, 1869) mentions 

 having used skim milk with good success. The Gooseberry Span- 

 worm of Europe, already referred to, is fought with a decoction of 



