THE PINE INVESTIGATION. 321 



probably the best results would be gained by keeping the in- 

 sects until the following spring when the conditions would be 

 more favorable for them to survive. A great many of the 

 larvae had entered the cork stoppers of the bottles, and had 

 made therein their cocoons in which to change to pupae. It was 

 therefore thought that this was the most. favorable conditions for 

 them to pass the winter, and that they had best be not dis- 

 turbed. It was feared, however, that the adults would not 

 survive, but since there was not a sufficient number of these to 

 justify a distribution to the timber companies, I decided to place 

 them in pine woods near Morgantown where a number of 

 trees were dying from the attack of the destructive bark bee- 

 tle, and on Oct. 10th, 1892, 50 adults and 25 active larvae were 

 placed on and in the bark of a group of dying scrub pines on 

 Mayfield Hill, about seven miles from Morgantown, this colony 

 being the first examples liberated in America. The liberated 

 adults were observed by myself and Prof. F. W. Rane, who ac- 

 companied me, to attack and devour the bark beetle, as well as 

 other species of bark beetles which occurred on the bark of 

 the trees. 



LETTER TO TIMBER COMPANIES, 



The parties who had contributed to the experiment were no- 

 tified of my return, and the results of the expedition in a letter 

 dated Oct. 13th, 1892, a copy of which is here given: 



October 13, 1892. 

 DEAK SIR: 



You will no doubt be interested to learn of my return from Europe, and 

 my success in finding an insect, which, I have every reason to believe will 

 prove very beneficial as a destroyer of our destructive pine bark beetle. 

 This beneficial insect, which has been named "The European Hark Beetle 

 Destroyer", was found very common in certain forests in Germany, where 

 it was feeding on a pine bark beetle similar in appearance and habits to 

 our destructive species. 



I had hoped to collect large numbers of the species to introduce into our 

 forests this fall, but on account of the cholera epidemic and the strict quar- 

 antine and fumigating precautions, 1 felt it would be impossible for me to 

 get live specimens to America in time for them to be of any service this 

 year. I therefore, collected only a sufficient number with which to carry 

 on experiments in the laboratory and green-house this winter, and after 

 arranging with parties in different sections of Germany to collect and for- 

 ward to us many thousands of the species next spring, I proceeded into 

 Switzerland on September 12th. to await an opportunity to return to 



