258 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 12 



NOTES ON LEPIDOPTEROUS BORERS FOUND IN PLANTS, 



WITH SPECIAL REFERENCE TO THE EUROPEAN 



CORN BORER 



By Edna Mosher 



The advent of the European corn borer, with its tremendous possi- 

 bilities for injury if ever introduced into the great corn-growing states, 

 has caused us to become much more concerned about the identity of 

 the various caterpillars found feeding inside the parts of plants. The 

 identity of the plant gives little help in this connection, since the corn 

 borer has a very wide range of food plants and seems anxious to add to 

 the list of those already known. Since lepidopterous larvae vary 

 considerably in their different stages as to colors and color patterns, 

 and there are many with black or brown prothoracic shields and similar 

 colors at the bases of the setae, it is necessary to go farther than this in 

 their identification. Easy keys are not available for the identification 

 of such species and this paper is offered in the hope that it may aid 

 field workers and others to be reasonably certain whether or not they 

 have found the European corn borer. Of course the matter would be 

 greatly simplified if we could include all the known species of borers in 

 this country, but since material for such a study is now impossible to 

 obtain, let us hope that our search for corn borers will bring to light, 

 not only species hitherto described, but new life histories as well. It 

 is appalling to think how little we know of the life histories, parasites, 

 etc., of this single genus Pyrausta, whose one renegade member is 

 costing us, not only great amounts of money but a great deal of time 

 and anxiety as well. 



Classification of Borers 



Lepidopterous borers, in the main, belong to a few families. Nearly 

 all of the species are provided with five pairs of prolegs, four abdominal 

 and one anal, and these are armed with chitinous hooks or crochets. 

 When these are absent the adfrontal area (Fig. 13, no. 29, adj.) and the 

 median spine-like spinneret on the labium will distinguish them from 

 larvae of any other order. This paper does not include leaf-miners, 

 borers in woody plants, or gall-making species. 



The character found most reliable so far in the determination of 

 lepidopterous larvae is the arrangement of setae on the various body 

 segments. Some other characters have been used, and it seems quite 

 possible that there are others available. In separating the families 

 mentioned here, the arrangement of setae on the prothorax and of the 

 hooks on the prolegs are sufficient for the majority of cases. The 



