1907.] PUBLIC DOCUMENT — No. 33. 199 



REPORT OF THE ENTOMOLOGISTS. 



C. H. FERNALD ; H. T. FERNALD. 



Outline of Work. 



Four main lines of work have occupied the attention of 

 the entomological division of the station during 1906 : corre- 

 spondence, experimental investigations, special research and 

 the preparation of results for publication. 



The correspondence during the year has been unusually 

 large in amount, and has extended over a much longer period 

 than is usual. The largest amount of this work generally 

 comes between the first of May and the end of Augaist, but 

 this year it began in March and continued until into Decem- 

 ber. Of course during the remaining months numerous letters 

 are received and answered, but the bulk of the correspondence 

 has now not only increased beyond that of j^revious years, 

 but has extended over a longer period. 



No unusual devastation has been reported during the past 

 year, but all of our injurious insects seem to have been abun- 

 dant, and have caused their share of loss in one line or 

 another. 



Experimental investigations have been begun or continued 

 from previous years along a number of lines. The prevalence 

 of the white fly in greenhouses has caused much loss, and in- 

 formation as to the methods of controlling this insect has 

 been in great demand. For this purpose fumigation with 

 hydrocyanic acid gas appears to be the most successful if made 

 at the proper intervals of time and in the proper way; but 

 this gas is also injurious to plants, and how much these can 

 stand under varying conditions of light, temperature, humid- 

 ity, lengtli of exposure to the fumes, etc., has not been de- 



