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l8 9i •] A New Herbarium Pest. 337 



less distinct, and the discal spot more intensified. The fringes 

 are concolorous with the ground color and with black dots 

 beyond the veins. 



This insect has become a source of positive alarm in the 

 Department herbarium on account of its rapid multiplication 

 and the harm it occasions. It behooves botanists to be on 

 the lookout for it and to adopt such measures as will insure 

 immunity from it, if dry specimens are being received from 

 Mexico and the southwest, or from herbaria in which it is 

 known to occur. The custom of poisoning dried plants with 

 corrosive sublimate to protect them from various enemies, such 

 as book mites, Psoci, etc., should give immunity from the 

 attacks of this insect if the poison has been thoroughly ap- 

 plied. If to the corrosive sublimate a quantity of arsenic is 

 added, the protection will be more effectual. I would also 

 recommend as very useful in disinfecting herbaria of this and 

 other pests an air-tight quarantine box of zinc or galvanized 

 iron in which the plants may be temporarily placed and sub- 

 mitted to the fumes of bisulphide of carbon, which are very 

 sure to destroy all insect life. Effective steps have already 

 been taken to prevent the sending out from the Department 

 of any infested specimens in future. 



The fact that this insect has appeared in dry plants from 

 the comparatively arid western regions may furnish a clew to 

 its original habit. It is presumable that it normally feeds on 

 the dead or dried plants of Mexico and adjacent arid regions, 

 and that it has simply adapted itself to the somewhat similar 

 conditions prevailing in herbaria. 



This is the first true Geometrid, so far as I know, recorded 

 as feeding on dry and dead vegetation. In the Pyralidina a 

 number of species are known to be not only truly carnivorous, 

 feeding on other insects, but also to feed upon grass and 

 rejectamenta as well as dead leaves. Some Tineina are also 

 known to have similar habits, while in the Deltoid group of 

 Noctuids several genera are known to feed on dead leaves. 



The illustrations, which have been prepared for Insect Life, 

 are used by permission of the Hon. Edwin Wilhts, Assistant 

 Secretary of Agriculture, who desires to give the facts in the 

 case as wide circulation as possible, and who is particularly 

 anxious that the Department shall not be the means of dis- 

 tributing any undesirable introductions. 



U. S. Dcpt. of Agric, Dm. of Entomology. 



