10 U. OF X. H. AGR. EXPERIMENT STATION [Bulletin 227 



"Whether because of a season clearly unfavorable to them or not, the 

 Eurojiean corn borer has not reached intense infestation in New 

 Hamjishire that we can discover, reports W. C. O'Kane. who has charge 

 of this project. The insect is very widely distributed, but at the same 

 time it is not plentiful in the sense that it has reached badly injurious 

 numbers in any one place. 



Accumulated data on its life history will shortly be published as a 

 })rogress report. 



Another phase of the investigation has had to do with the sjiiracular 

 closing apparatus and its performance at A'arious stages of hiberna- 

 tion of the larva. A critical study of the ai)paratus and its perform- 

 ance was made, including its anatomy, its relation to the tracheal 

 system, and its status, both as the larva is apin-oaching hibernation in 

 the fall and as it is emerging from hibernation in the spring. Inter- 

 esting results were secured, and these have been brought together by 

 M. F. Crowell in Technical Bulletin 30. 



The Stalk Borer— [Hatch Fiind) 



The effect of the unusual season has not been as marked on the 

 stalk borer as on the European corn borer. Dates for transformations 

 have been later than those of last year, however, reports P. R. Lowry; 

 for example, hatching of over-wintering eggs began May 26 this year 

 as compared with May 18 last year. Pupation began Aug. 10 as 

 compared with Aug. 4, and the first adults emerged Sept. 10 as com- 

 pared with Sept. 1 last year. 



A further study of parasites has been made. The species of Diptera 

 that was found last year is again plentiful, and is the most marked 

 natural enemy of this insect under New Hampshire conditions. A 

 second species of Hymenoptera has been found this year, making two 

 in all. Its identity will be determined when the adults have been 

 secured. 



Black YXies— [Hatch Fund) 



The study of black flies, including ecological data secured at eighty- 

 eight observation points and extending over a long period, as well as 

 further experiments in control, was brought to a close in the year just 

 passed. The material has been tabulated and prepared for publication 

 as Technical Bulletin 32. 



White Pine Weevil — • [Purnell Fund) 



Life history studies of the white pine wee^'il have been in hand for 

 the past year. Interesting facts have been secured as to the habits of 

 the weevils, their manner of gaining access to the leader, the process 

 of egg-laying, the developmental dates of the larva, and the hiberna- 

 tion habits of the adults. Specimens of a related species have been 

 found attacking the roots of small stunted pines. 



This work is planned to continue for the coming season and to 

 include a study of parasites and an investigation of the performance 

 of weevils under various conditions as to pure and mixed stands. 



