248 



to the prosecution of such work. The beneficial insects previ- 

 ously introduced— including the fruit fly, melon fly, dung fly 

 and corn leaf-hopper parasites — have been propagated and dis- 

 tributed without interruption, although there is no question about 

 their establishment in the islands. The reason for the continued 

 distribution of the parasites is the necessity of re-establishing or 

 renevving the parasites in particular localities where through de- 

 pletion or disappearance of the host the parasites become dimin- 

 ished or disappear, and with the reappearance of the host are 

 not present in sufficient numbers to be an effective check to its 

 destructiveness. This is especially true in the case of those 

 species with weak flight, like Tefrastichus and Paranagrns. The 

 latter parasite requires frequent renewal on the lowlands on ac- 

 count of the discontinuity in the corn crop. The distribution 

 of the different parasites during the year was: fruit fly, 13,505; 

 melon fly, 16,288; dung fly, 5,570; corn leaf-hopper, 264,800, or 

 a total of 300,163. 



It is gratifying to have confirmation of the increasing eft'ective- 

 ness of the fruit fly parasites in the investigations of the United 

 States Bureau of Entomology office in Hawaii, and the excep- 

 tionally large corn crop of this year testifies to the effectiveness 

 of the leaf-hopper control when managed by progressive farmers. 

 Within a few days it has been learned that an introduction of 

 1917, a wasp brought from the Philippines to prey upon cock- 

 roaches, has become established in the islands. 



The inability to undertake new work has afforded leisure for 

 study, and many of the problems connected with the control of 

 insect pests have been gone over afresh. It has also allowed the 

 entomologists to undertake a considerable amount of systematic 

 work on the Board's collection of insects, which has been greatly 

 improved and on which four papers have been published and two 

 others are in the course of preparation. 



ANIMAL INDUSTRY. 



During the fiscal year there has been the same steady progress 

 in the development of the different classes of live stock and the 

 suppression of contagious diseases within the Territory which has 

 been noted in past years. The rules and regulations cover- 

 ing the importation of live stock have proven effective in pre- 

 venting the introduction of the many animal scourges which are 

 causing enormous animal losses in other parts of the world. 

 This effectiveness has been greatly enhanced by recent revision 

 and addition thereto. 



Live stock importations have practically been confined to pure- 

 bred registered animals of the different classes for the continued 

 improvement of the herds here. That considerable has been ac- 

 complished in this direction is evidenced by the fact that the Terri- 

 tory is now self-supporting as far as beef and pork is concerned 



