6 THE GIPSY. MOTH AS A FOREST INSECT. 



under the direction of Dr. E. A. Mark and Dr. Theobald Smith, 

 working more or less independently, and stOl the results were nega- 

 tive. The present writer, in connection Avdth the work of parasite 

 importation, conducted experiments of a similar nature but with the 

 usual outcome. The difficulty in every case was due to the fact 

 that it was impossible to secure healthy caterpillars for either the 

 experiment or its check. It made no difference whether the cater- 

 pillars were fed with the infected food or not, large numbers would 

 die in any event, and there seemed to be no noticeable difference 

 between the mortality in the experiments and in the checks. 



It remained for Mr. William Reiff, at one time a laboratory assist- 

 ant in the Bussey Institution, to claim success where others had 

 failed. His experiments were, in their essential characters, like those 

 of his predecessors. He fed some caterpillars upon an unfavorable 

 food, and they contracted the disease and died, exactly as had resulted 

 in all other recent attempts to rear caterpillars in the laboratory from 

 American eggs. When the sick and dead individuals were placed 

 upon badly infested trees in the field a mortality was noticed among 

 the other caterpillars in the vicinity. The fact was cheerfully ignored 

 that a similar mortality might be observed in every other locality 

 where the same degree of infestation prevailed, and no attempt was 

 made systematically to determine exactly what happened in these 

 other places. In this most important respect the experunents con- 

 ducted by Mr. Reiff differed from those conducted by Dr. Johnson. 



Such a series of check observations has been made the past sea- 

 son, quite incidentally, in connection with the field-observation work 

 as conducted by Mr. A. F. Burgess of the Bureau of Entomology. 

 The final results of this work for the season are not yet available, but 

 the writer, who has personally visited the majority of the observation 

 points, of which perhaps 20 per cent chanced to be in the immediate 

 vicinity of disease plantings of the summer before, has been abso- 

 lutely unable to distinguish a single point of difference between the 

 treated and the untreated' localities. In everj- badly infested locaHty 

 complete or partial defoliation with all its attendant consequences 

 resulted. The severity of the injury differed notably in different 

 localities, as was to be expected, but if extreme instances were to be 

 cited it would not be difficult to select localities where no disease was 

 planted in which conditions at the close of the season were very 

 much better than in others where plantings had been made. 



Nor is there anything unusual anywhere in the infested territorv 

 to differentiate conditions this fall from those prevailing a year or two 

 ago. In fact it is the writer's personal impression that rather more 

 pine has been seriously injured in 1912 than in 1911, and that the con- 

 dition of the oak is worse than he has ever seen it before. In short, 

 nothing whatever that is tangible has yet come to the attention of 



