462 REPORT OP THE COMMISSIONER OF AGRICULTURE. 



more room for it by destroying other less injurious and smooth, 

 species; secondly, the use of the wooden tree-boxes, which afford 

 such excellent winter shelter for the cocoons. 



Some recent experience is recorded with regard to Joint Worms, 

 and the interesting fact is brought out that alternation of generation 

 occurs among them, and that in the genus Isosoma, to which they 

 belong, two forms, which have hitherto been considered good species, 

 are in reality seasonal dimorphic forms of one and the same species, 

 as I have always suspected would prove to be the case. 



The year 1886 may be said, entomologically, to have been an ordi- 

 nary one, and notwithstanding the exceptional injury by some, there 

 •has been, perhaps, less damage than usual from injurious species. 



Among these last must be mentioned the Hop Aphis {Fhorodoii 

 humuli), which was so destructive in the great hop regions of New 

 York State as to have caused an almost total loss. The best e^adence 

 I have been able to obtain from correspondents is that in a great 

 many cases no harvest was made, and on an average only about 10 

 per cent, was harvested. In this connection I have taken steps to 

 carry on a series of practical experiments the coming year, and I may 

 state as a matter of interest that, from investigations made last Sep- 

 tember in the hop fields I am led to believe that I have discovered 

 the winter egg of this hop-louse upon plum trees, so that its mode of 

 hibernation, which has hitherto been a mystery, has thus been set- 

 tled. Full verification of this fact, however, cannot be obtained 

 without another season's observation, and for this reason I have been 

 unwilling so far to publish anything in detail. 



In my last report I showed that, so far as experiments in silk-cult- 

 ure are concerned, no decisive results could well be hoped for until 

 the Serrell automatic reel could be tested at some point in Washing- 

 ton where the details could be well controlled and observations made 

 by myself and assistants, and where the work could be carried on for 

 at least two years. Congress therefore appropriated 610,000 for this 

 particular j^urpose, and the reeling stations at San Francisco, New 

 Orleans, and Philadelx)hia have been abandoned. The brief report 

 of the work in this direction, which will be found in the following 

 Images, must be looked upon as preliminary; for, while the figures 

 given look somewhat discouraging, no fair and proper estimate can 

 be made before another year. The confirmation which our reeling 

 has so far given of the value of the Osage Orange as silk-worm food 

 is interesting, and entirely in keeping with what I expected and what 

 I have previously recorded. 



Work has been continued at the apicultural station at Aurora, 111. , 

 as far as the means would permit, and a report on some of the ex- 

 periments by Nelson W. McLain, in charge of the station, is em- 

 bodied, while some further reports will be included in a special bul- 

 letin, I have endeavored by occasional consultations with Mr. 

 McLain to keep the experiments in lines that have been more or less 

 neglected by bee-keepers and in which there was hope of valuable 

 results. The most important of these are in the direction of control- 

 ling fertilization. Most of the improvement in bee-culture in the 

 past has been in the direction of mechanical appliances, while these 

 experiments have in mind the improvement of the bee itself, so as 

 to increase its honey-yielding power, and thus advance the interest 

 in the same way that the dairy interest has been advanced by improv- 

 ing the milk and butter producing qualities of the coav. 



A year ago Congress added $5,000 to the appropriation of the Divis- 



