EEPOET ON SOME OF THE IKTUKIOUS INSECTS OF CALL 



FOENIA. 



By D. W. Coquillett, Special Agent. 



LETTER OF SUBMITTAL. 



Washington, D. C, November 7, 1893. 

 Sir: I herewith submit my annual report for the year 1893. This consists prin- 

 cipally of accounts of several kinds of leaf-eating caterpillars which attack various 

 kinds of fruit and nut trees in California. 

 Very respectfully, yours, 



D. W. Coquillett. 

 Dr. C. V. Eiley, 



U. S. Entomologist. 



The Walnut Span-worm (Boarmia plumogeraria Hulst). — In Bulletin 

 No. 30 (pp. 26-29) of this Division, I gave an account of a span- worm 

 that had occasioned very serious damage to English- walnut trees in a 

 certain locality in southern California. At the time of submitting that 

 report none of the moths had issued from the chrysalis state, and I was 

 therefore unable to give the technical name of the insect. Moths began 

 to emerge January 5, 1893, and continued at intervals to March 25. 



Owing to the fact that the female is wingless, and that the chrysalis 

 state is passed in a cell in the earth, we are enabled to prevent the rav- 

 ages of this pest by simply preventing the female moths from ascending 

 the trees and depositing their eggs. To accomplish this many devices 

 and substances have been used, as in the case of the canker-worms, the 

 females of which are wingless, and the transformations of which are 

 similar to those of the present species; hence every remedy that can 

 be successfully used against the canker-worms is equally applicable to 

 the present species. 



Perhaps the simplest device to use for the purpose of preventing the 

 female moths from ascending the tree consists of a band of tarred 

 building paper about 6 inches wide, wrapped around the tree close 

 to the ground and fastened with a stout string passed around the band 

 near its upper edge. The lower edge of the band should be pressed 

 firmly into the earth, so that no portion of the tree below the band is 

 exposed to view. Some kind of sticky substance should be painted or 

 smeared around the upper portion of this band to a distance of two or 

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