ANNUAL REPORT, 1939 65 



grape canes reach 6 to 8 inches in length the beetles begin to lay eggs and continue 

 for about a month. The egg is usually laid in a small cavity eaten in the stem 

 just above a ring of holes which girdle the cane and cause it to break. The girdle 

 cut, which is made by twelve or more punctuies in a ring around the stem, ap- 

 parently serves to eliminate or reduce the pressure of the growing cane so that the 

 larva can hatch and feed more easily. 



The life cycle was completed in about 51 days, being divided into 11.6 days 

 for incubation of the egg, 26.8 days for feeding of the larva, and 12.4 days for 

 pupation. The beetles, which emerge early in August, feed slightly on the veins 

 on the under side of the leaf before going into hibernation. In 171 girdled canes 

 examined between June 19 and August 10, 40 percent of the egg punctures were 

 empty or contained dead eggs. Spraying potted grape vines with lead arsenate 

 and calcium arsenate greatly reduced injury by the beetle but did not prevent the 

 canes from being girdled. 



Liberation of Parasites of the European Earwig. (W. D. Whitcomb, VValtham.) 

 The European earwig is now established in southern Bristol County, especially 

 in the vicinity of Fall River, Taunton, and New Bedford, where it is a serious 

 annoyance to housekeepers and a minor pesr of plants. 



In June and July, 1939, 1,000 adult flies of the earwig parasite, Bigonichaeta 

 setipennis, were sent in four shipments to Boston by Air Express from the Puyal- 

 lup, Washington, laboratory of the United States Bureau of Entomology and 

 Plant Quarantine, and were liberated in the infested area. In spite of the long 

 trip by airplane 90.6 peicent of these parasitic flies were alive and healthy when 

 released. 



Previous to the liberation of the parasites, about forty earwig traps or hiding 

 blocks had been placed at strategic points in the infested area and examined fre- 

 quently to determine the presence of a suitable number of earwigs for effective 

 parasite establishment. As a result of the trap examinations, parasites were 

 liberated at eleven locations a? follows: Fall River 4, Dighton and North Dighton 

 3, Somerset 2, and Segreganset and Assonet 1 each. 



Examinations of the earwig traps for the presence of puparia of the parasitic 

 fly were made on August 16, September 14, October 10, and November 14, 1939. 

 On August 16, 2 puparia of the parasitic fly were found at a liberation point on 

 North Street, Somerset. No other parasites were recovered in any traps at any 

 of the examinations. 



Traps will be returned ne.xt year to the points where parasites were released, 

 for it is reported that, if the parasites become established, they are more likely 

 to be recovered during the following season than immediately after the flies 

 are released. 



Insects Concerned in the Dispersal of Dutch Elm Disease. (W. B. Becker.) 

 An article entitled "Larval development of the native elm bark beetle, Hylurgo- 

 pintis rufipes (Eich.), in Massachusetts" was published in the Journal of Economic 

 Entomology?,! (No. 1):112-121, 1939 (Contribution 309). 



Mr. W. E. Tomlinson of the Waltham Field Station again cooperated by con- 

 tinuing experiments on the biology of the native elm bark beetle and the smaller 

 European elm bark beetle, in Waltham. The following records were taken. 



The Native Elm Bark Beetle, Hylurgopinus rufipes (Eich.). Adults reared 

 from eggs laid in American elm logs in late April and early May of 1938 began to 

 emerge in early August of the same year. No beetles of this brood emerged from 

 these logs during 1939. Since 1934 when the beetle was first studied at Amherst, 

 and during the time it has been studied at W'altham, no adults of the early spring 

 brood have been obseived to emerge after the late fall of the same year, although 



