262 ANNUAL REPORTS OF DErARTMENT OF AGRICULTURE. 



therefore, is to cooperate with the Federal Horticultural Board in 

 safeguarding against further introductions of such insects from the 

 sources named. The work of the last year under this station has 

 had particular relation to several important insect enemies of the 

 aA'ocado. Alread}^ effective means of control of the principal avocado 

 insects have been devised, notably with respect to leaf-infesting mites, 

 to species of thrips, and several scale insects. Work has also been 

 done with respect to insect enemies af the mango and the papaya. 



Studies of greenhouse insects. Under this project, life-history 

 studies and methods of controlling the chrysanthemum midge, a very 

 important injurious insect of this plant in eastern greenhouses, have 

 been completed and presented for publication. A bulletin (Depart- 

 ment Bulletin 778) has also been published during the year giving the 

 life history and methods of controlling the rose midge. Work has 

 also been done with respect to the effective utilization of various in- 

 secticides and in the general problem of fumigating plant houses. 



Mediterranean fruit ily and :melon fly. This work is a con- 

 tinuing one, and has been carried on at the bureau's laboratory in 

 Honolulu. The research features of the work have consisted in fur- 

 ther studies of control b}^ the agency of parasites and natural enemies. 

 The principal work, however, has remained as heretofore in the in- 

 spection and certification of bananas, pineapples, taro, and coconuts 

 for shipment from Hawaii to the mainland of the United States. 



" Geographical distribution of fruit flies. The work under this 

 project has for its special object the surve3^s of districts contiguous to 

 the United States, from which the importation of fruit and plants 

 may be the means of introduction of fruit flies and other enemies of 

 important fruit crops. During the past fiscal year the field work 

 under this project has involved explorations of the Panama Canal 

 Zone, British Guiana, and the West Indian Islands of Barbados, 

 Trinidad, Tobago, and Gi'enada, continuing the work which was done 

 the previous year in Cuba, Jamaica. Dominican Republic, and the 

 Virgin Islands. In the course of this work a great many insects 

 have been collected and studied of known or potential economic im- 

 portance and in addition a very considerable miscellaneous collection 

 of insects has been made. The investigations were conducted in plant 

 gardens maintained by the local departments of agriculture of the 

 different islands and such general surveys as were^possible within 

 the time limits. Particular attention has been paid throughout the 

 work to fruit flies, scale insects, and such other pests as are particu- 

 larly likely to be carried from country to country by traffic in fruits 

 and plants. A good portion of the time of the expert engaged in this 

 work is necessarily devoted to the identification of the material col- 

 lected and the working up of results. 



Investigation of fruit flies and otpier tropical and subtropical 

 FRUIT insects IN THE Canal Zone, Panama. This is a new project 

 which has been established in cooperation with the authorities gov- 

 erning the Panama Canal Zone and the Federal Horticultural Board 

 to study the important insects infesting tropical and subtropical 

 fruits, cultures of which are being developed under the encourage- 

 ment of the Government authorities in the zone. The impoi*tance 

 of this investigation is due to the fact that the several important 



