832 MAUD D. HAVILAND 



iiccordiii^' to the recent investigations of Pemberton and 

 Willard (9). Among the parasites introduced to control the 

 Mediterranean fruit-fly (Ceratitis c a pit at a, Wied.) were 

 two species, Opius humilis, Silvestri, and Diachasma 

 t r y o n i , Cameron. It has now been shown that epiparasitism 

 is common between Opius and Diachasma, and that in 

 such a case Diachasma is nearly always victorious. Thus 

 Diachasma is gradually suppressing p i u h in Hawaii ; 

 and, as the authors point out, this result is the more deplorable 

 in that Opius is not only equally efficient as a parasite, 

 but is actually more prolific than its rival, and if left to itself 

 would destroy a larger number of fly lar\ ae. The situation has 

 been further complicated by the introduction of a Chalcid, 

 Tetrastichus giffordianus. This form is very prolific ; 

 but, as it is almost always epiparasitic, it is ineffective as a con- 

 trol of the pest, and generally causes the death of the Opius or 

 Diachasma larva when it comes into competition with them. 



Fiske and Thompson (4) have shown that the larvae of certain 

 Saturniidae are parasitized by the hymenopterons, Ophion, 

 T h e r o n i a , and !S p i 1 o c r y p t e s . All three are primary 

 parasites, but epiparasitism is frequent, and when it occurs, 

 Theronia and Spilocryptes respectively overcome 

 p h i o n . In competition between H p i 1 o c r y p t e s and 

 Theronia, the first generally is the conqueror; but 

 Theronia, it appears, dies of starvation from destruction 

 of its food-supply rather than by direct attack. 



Timberlake investigated the bionomics of Coccophagus 

 lecanii. Fitch (14), a parasite of Coccus hesperidum, 

 which is more frequently reared as a hyperparasite from 

 another primary parasite, M i c r o t e r y s . According to this 

 observer, Coccophagus is thelyotokous when a primary 

 parasite, producing generations of females only ; but when 

 it is reared as a hyperparasite, the resulting imagos are all 

 males — a state of things so far unparalleled. 



Howard and Fiske (7) in their report on the measures taken 

 to control the gipsy and brown-tail moths in the United 

 States, record many interesting observations on the bionomics 



