150 HATCH EXPERIMENT STATION. [Jan. 



gathered arid recorded. The card catalogue has been kept 

 abreast of the new pubHcations and improved in many ways, 

 and requests for the information it contains are frequently 

 received from other stations and from individuals. 



Some study has been given to the carnation twitter, and 

 the identity of the insect causing this trouble has been ascer- 

 tained with considerable though not absolute certainty. 

 Further investigations on this subject will be made during 

 the coming year if material to stud}^ can be obtained. 



Special researches have also been continued on the Asilidte 

 or robber flies ; the Pyralida^ a group including many very 

 injurious insects ; the Bombinfe or bumble bees and their 

 habits ; and on the Sphecidti? or digger wasps, these studies 

 being of the entire groups ; while a Cecidomyiid on oak, the 

 stalk borer and several other species have received special 

 attention individually. 



The erection of a new greenhouse during the summer has 

 greatly improved the facilities of the division for entomo- 

 logical research, besides being an excellent example of modern 

 greenhouse construction. With a house which is reasonably 

 tight and which can be kept warm during the winter it has 

 been possible to begin a series of experiments to determine 

 the resistant power of various forcing crops to fumigation. 

 The business of raising crops under glass in Massachusetts 

 is a very large one, and in too many places is greatly inter- 

 fered with by the presence of insects which can only be con- 

 trolled by fumigation with Iwdrocyanic acid gas. The strength 

 of fumigation necessary to destroy these insects is now well 

 known in most cases, but the charge which the plants can 

 resist under all conditions of growth is not ; and many an 

 owner has refused to fumigate a badly infested house for fear 

 of killing his plants along with the insects. From the ex- 

 periments now under way, and which it will require several 

 years to complete, it is believed that data can be obtained of 

 such a nature that any person ^vho desires to treat a green- 

 house will be able to do so with entire; safety to the plants, 

 !uul yet kill (he insects which may be present. 



