THE PROGRESS OF SCOLIA MANILA ASHM. 



IN HAWAII. 



By F. MuiR, 

 H. S. P. A. Experiment Station, Honolulu. 



In a former article* the introduction of Scolia manilce into, 

 and its establishment in, the Hawaiian Islands was described. 

 At that time the wasp was well established but ^ its host, 

 Anomala orientalis, was very abundant and doing great damage. 



As an example of the difference between the conditions 

 then and now the following comparisons are of interest. In 

 1917 from one-twentieth of an acre, 3500 Anomala grubs were 

 collected from between the rows without digging around the 

 roots of the sugar cane. Now in the same locality but over a 

 larger area only four grubs could be found by following the 

 plow and searching. In another locality 104 eggs, 181 grubs, 

 7 pup^e and 10 adults were collected from around the roots of 

 one stool of sugar cane, now in the same locality one can only 

 iind a stray specimen after considerable search. 



The parasite has extended its range beyond the area infested 

 by Anomala orientalis, and is now working on Adoretus tenui- 

 maculatus, a beetle common all over the archipelago. 



The reduction of the Anomala is due solely to the action of 

 the Scolia as all other factors are the same as previous to the 

 introduction of the Scolia, w^hen the Anomala was constantly 

 increasing and spreading. 



The phenomenal reduction of A. orientalis has raised the 

 question as to the possibility of its eventual extinction. Should 

 the Scolia maintain itself upon the Adoretus but show a great 

 predilection for the Anomala such a thing may happen. The 

 final outcome is being watched with great interest. 



"Ann. Ent. Soc. Am., X, p. 207 (1917). 



171 



