410 Rei'ort of the Department of E>tomology of the 



METHODS OF CONTROL. 



The present situation regarding the ermine moths suggests the 

 great importance of a careful inspection of nurseries, especially of 

 the plantings of foreign-grown seedlings. Owing to the incon- 

 spicuousness of the egg masses, due to their small size and their 

 color, which resembles that of the bark, very few of them are likely to 

 be detected at the customary examination at the time of spring deliv- 

 eries when the stock is being unpacked and sorted. The most effect- 

 ive work can be done during June, when the inspector should look 

 for plants which show the webs or tents of the insect. Plates XLIV 

 and XLV. All infested plants should be uprooted and destroyed. 

 Experience has demonstrated very clearly the importance of more 

 than one examination, and if two are made one inspection should 

 be planned for the latter part of June when the work of the insects 

 will be more conspicuous because the caterpillars are then full grown 

 and Vv'ill have spun their larger webs. If the work is delayed beyond 

 this time there is danger that the insects may have pupated and 

 transformed to moths. As insects may have escaped from previous 

 infestations, premises adjoining nurseries should be similarly 

 examined. 



The caterpillars are quite susceptible to arsenical poisons and 

 should it ever become necessary to combat them in plantings of 

 older trees little or no modification will probably be required in 

 existing spraying practices for orchards. 



ACKNOWLEDGMENTS. 



For literature and specimens of insects we are indebted to Prof. 

 George H. Carpenter, Dublin, Ireland; Prof. R. Stewart Mac Dougall, 

 Edinburgh, Scotland; M. J. de Joannis and Dr. Paul Marchal, Paris, 

 France; Dr. L. Reh, Hamburg, Germany; Mr. Sigismond Mok- 

 shetsky, Crimea, Russia; Prof. W. M. Schoyen, Christiania, Norway; 

 Prof. Sven Lampa, Stockholm, Sweden; Prof. J. Ritzema Bos, 

 Wageningen, Holland, and Dr. S. I. Kuwana, Tokio, Japan. 



Prof. C. H. Fernald allowed the use of his library and the card 

 catalogue of entomological literature at the Massachusetts Agricul- 

 tural College, for which courtesies we are under great obligations. 

 Prof. J. H. Comstock kindly permitted the use of the library of the 

 Department of Entomology of Cornell University for reference pur- 

 poses. For the compilation of the bibliographies, aside from refer- 

 ences to economic literature, we are largely indebted to Mr. H. 

 E. Hodgkiss of this department. The translation of Mokshetsky's 

 treatise was the work of the late Dr. Francis P. Nash of Hobart 

 College. His interest in our study and his disinterested labor amid 

 the exacting duties of his own specialty calls for our gratitude and 

 appreciation of his scholarly attainments. 



