8 



bred iii confinement only. These particular parasites were bred from the 

 most of the Larger coccinellid larvae, yet were found most numerous 

 upon Orcus. During - my last visit to Toowoomba, Queensland (April 

 0-11, lSOi^the deadly work of the Homalotylus was plainly illustrated. 

 In one orange orchard most of the leaves had dropped off from the 

 upper parts of many trees, as also a large part of the fruit, from the 

 effects of the Ked Scale, which is always most numerous during the 

 driest and hottest part of the year (March and April).* It was hard 

 work here to gather a couple of dozen of Orcus chalybeus Boid., and 0. 

 australasia Boisd., within live hours, yet the dead and parasitized 

 larvae were present by the hundreds. Something similar was noticed 

 near Sydney upon a couple of young orange trees that appeared to be 

 in a dying condition; yet a few weeks' work of the predaceous insects 

 upon the scales and a shower of rain brought the trees again into the 

 best condition, with no apparent Ked Scale whatever. It is during 

 the hot and dry weather in Australia that the Eed Scale becomes most 

 prevalent and the insects preying upon it rarest. Moisture appears to 

 be more favorable to the development of the Coccinellidae and unfavor- 

 able to their enemies, as it also is to the copious growth of the fungoids 

 destructive to Coccidse. It has been estimated that about 50 per cent 

 of the larvae of the first brood of Orcus were destroyed by the parasites 

 alone, and, as in the case just mentioned at Toowoomba, nearly the 

 entire lot of the second brood were killed; yet this must be subject to 

 variation. 



The more prominent enemies to the Orcus are the various birds which 

 feed on the larvae as well as on the mature insects; numerous small 

 lizards that inhabit the trees and, what are considered otherwise bene- 

 ficial insects, numerous mantis eat their larva? with avidity. Bepeat- 

 edly these have been observed to completely devour a full-grown larva 

 in less than one minute, and since they have such well-known and 

 continuous appetites, they must devour large numbers daily. 



Probably these parasites (yet another species) upon Rkizobius are 

 still more numerous. Hundreds of parasitized larvae of A\ centralis 

 Muls. were found at Melbourne, under the bark of Eucalyptus that was 

 infested with Eriococcus eucalypti Mask., while the healthy insects 

 were but few in numbers; here at least, and with the other forms as 

 well likely, nature has come to help in providing a secondary parasite 

 that preys upon the Homaletylus larva. The same condition of things 

 exists in the closely-related species, R. dcbilis Black., that preys upon 

 the Black Scale on the olive at Adelaide. In addition to the parasites 

 destroying its larva, a second species was found destroying most of the 



* This orchard is situated near the top of a very steep hill exposed to strong winds. 

 The SOU is a heavy red clay, and the rain would wash down most of the top soil 

 without giving sufficient moisture to the roots helow. The unsuitable condition 

 more than the scales may be the cause of the trees losing part of their leaves aud 

 fruit. 



