December, '11] quayle: scale insect parasitism 513 



scale in its younger stages but are less numerous than Comys fusca. 

 This scale is also said to be kept in check through the work of the 

 above parasite, A statistical study of the parasitism of this scale 

 made a few years ago^ showed that, in 67,000 scales examined in all 

 parts of the state, the maximum in any orchard was 47.6 per cent, 

 and the minimum in any orchard 1.9 per cent, with a general average 

 for the whole state of 12 per cent. This represents but a single season's 

 observations and no doubt in some cases may run higher than that 

 given, but nevertheless it is not within the facts to state that this 

 scale is held in check by Comys fusca. 



PURPLE SCALE 



{Lepidosaphes heckii Newm.) 



This scale has always been considered freer from parasites than 

 any of the scales of economic importance in the State. While this, 

 in general, is true and purple scale material will usually be obtained 

 with no evidence of parasitism, yet in certain sections a considerable 

 amount of parasitism may occur. The only parasite taken from this 

 scale thus far, is Aspidiotiphagus citrinus Craw. A few cases have 

 been found where the maximum parasitization ran between 40 and 

 50 per cent. 



COTTONY CUSHION SCALE 



{I eery a purehasi Mask.) 



A parasite that was introduced at the same time as Novius eardinalis 

 to prey upon the cottony cushion scale was the dipterous species 

 Cryptoehcetum icerya Will. On account of the overshadowing results 

 of N. eardinalis this internal parasite was largely forgotten. At the 

 present time it is not uncommon to find this parasite, but it is still 

 much less important than the beetle. The heaviest parasitism by 

 Cryptoehcetum was observed on cottony cushion scale infesting an 

 acacia tree, and without making actual counts, the percentage seemed 

 to run at probably 50 or 60 per cent. 



PREDACEOUS ENEMIES 



Coccinellids, while not coming within parasitic enemies in the 

 narrower sense, are often nevertheless included, and a few will be 

 here briefly considered. 



The one importation that stands preeminently above all others is 

 Novius eardinalis concerning which every entomologist is familiar. 

 The cottony cushion scale is no longer an important pest in the State, 



1 Science, May 15, 1908. 



