216 ANNUAL REPORTS OF DEPARTMENT OF AGRICULTURE. 



colonies being liberated, containing 12,286,000 individuals. Re- 

 coveries from colonies previously planted in the field have been very 

 satisfactory, indicating that both of these egg parasites are doing 

 good work. 



Apanteles lacteicolor, a parasite which attacks small caterpillars 

 of the gipsy and brown-tail moths, has been recovered in greater 

 numbers than during the previous years. Meteorus versicolor and 

 another imported Apanteles, A. melanoscelis, have increased satis- 

 factorily in most of the colonies where they were liberated and have 

 spread over a large area from the original colony site. Specimens 

 have been secured this year so that several new colonies could be 

 liberated. 



The imported tachinid fly Compsilura concinnata has been recov- 

 ered in satisfactory numbers this year, and as it attacks many species 

 of native caterpillars it is a very beneficial insect. Another imported 

 tachinid, Zygobothria nidicola, has been found more abundantly 

 than before. The Calosoma beetle has continued its good work 

 although apparently not so numerous in certain localities as it was 

 last year. 



DECIDUOUS-FRUIT INSECT INVESTIGATIONS. 



Investigations of insects affecting deciduous fruits have been car- 

 ried on under the direction of Dr. A. L. Quaintance, as in former 

 years. 



Apple insects. — The studies of the codling moth in progress in 

 Colorado in cooperation with the Colorado Agricultural Experiment 

 Station have yielded much valuable information and are being con- 

 ducted on a larger scale. Laboratory life-history studies have shown 

 that there are in the Grand Valley two broods of larvse and a partial 

 third brood each year. An investigation has been carried on as to 

 the distance the moths can fly, day and night records of egg laying 

 have been made, the development of the larvae on the fruit and shoots 

 of the apple has been studied, and a band trap has been devised for 

 use around the trunk and branches of the apple trees which permits 

 the larva? to enter to pupate but prevents the exit of moths. This 

 trap has been put to a thorough test and has been found to be of 

 great value in codling-moth control. It will doubtless be adopted 

 by orchardists, since it does away with the need of frequent exami- 

 nation of bands for the destruction of larvae. Orchard spraying and 

 dusting experiments on a large scale are under way, the plats being 

 so arranged that the results should indicate the most effective times 

 and the minimum number of applications of poison for the control 

 of the codling moth under arid conditions. 



The investigation of apple-tree borers has been continued and 

 extended. A detailed account of the roundheaded apple-tree borer 

 is in course of preparation. The period during which this insect, in 

 its larval stage, bores into trees has been found to vary from one to 

 at least four years. It has also been found that the common service 

 tree is very largely responsible for the distribution of this borer in 

 the eastern part of the United States. The proximity of the service 

 trees and a few other trees in the woods to young orchards results 

 in a prompt infestation by this insect. Since the adult females mi- 



