June, '13] TIMBERLAIvE: PARASITES COCCUS HESPERIDUM 295 



more may mature. This Aphycus is able to pass through many 

 generations a year, as it develops from egg to adult in about eighteen 

 days at summer temperature. In many respects its life history is 

 similar to that of Microterys flavus, which will be treated more fully. 



The other new species of Aphycus is extremely rare and has been 

 found only at Carpenteria, near Santa Barbara, and at Avalon, 

 Catalina Island. 



Microterys flavus (Howard) 



Microterys flavus (formerly placed in the old genus Encyrtus) is 

 the largest and the most interesting of all the parasites of the soft 

 scale found in California. It is likewise effective to no small degree 

 and would have been given first place in the above list were it not for 

 two considerations : first, it does not seem to be able to survive in any 

 abundance wherever fumigation is extensively practised; and, secondly, 

 it is a parasite of gravid or even mature scales, which in many instances 

 leave a few offspring to two or three hundred before succumbing. 



This species is found throughout central and southern California, 

 but it is much less abundant in Los Angeles County than it is near 

 San Diego and Santa Barbara, or throughout the central part of the 

 state. Although originally described from California it was perhaps 

 introduced with its host many years ago through commerce. It has 

 been reported also from Ceylon, Ontario and several Eastern States. 

 Other recorded hosts in America are Lecanium corni Bouche and 

 Pulvinaria vitis (Linn.), but it seems to attack only the soft scale as a 

 rule in California. 



This parasite is attacked by all of the hyperparasites that were 

 enumerated above, but its abundance is hardly modified by them as a 

 rule, and only one case has been found where it was apparently not able 

 to hold its own. In cases of superparasitism where there is a struggle 

 for the possession of the host between Microterys and some other para- 

 site such as Aphycus, the former is generally worsted, probably on 

 account of its specialized larval habits. When the struggle is between 

 Microterys and Coccophagus lunulatus, the most frequent and probably 

 the invariable outcome is that both succumb. In observed instances 

 the Microterys has been starved by lack of sufficient food, as it does not 

 attack the Coccophagus larva or pupa, and the latter succumbs be- 

 cause of the premature death of the host. Coccophagus lecanii is 

 generally a hyperparasite when it comes into conflict with Microterys, 

 but one instance has been observed where it was superparasitic. In 

 this case the Microterys larva was overcome while still small, and the 

 Coccophagus developed as a j^rimary parasite. 



The Microterys female is a pretty, little Encyrtine chalcid of deep 



