16 



The inter-relationship of the parasites themselves is also considered, 

 Hjrperparasitism denotes any stage of parasitism other than primary, 

 though a parasite of a predaceous insect, such as a Coccinellid, is not a 

 hyperparasite. Indirect parasitism is defined as ' " that tN'pe of symbiosis 

 in which the one parasite attacks a host-insect upon which it is itself 

 incapable of breeding for the sake of the primary parasite that it may 

 harbour." Perilampus liyalinus is cited as an example among the 

 Chalcidoids and Mesochorus 'pallipes among the Ichneumons. 



True secondary parasitism, which is of very common occurrence 

 in nature and of great importance in the natural control of insects, is 

 defined as that tA*pe of symbiosis where a parasite destroys a primary 

 parasite by direct attack and not through the medium of the host of 

 the primary parasite. This t^^e is very important in the control of 

 injurious insects, and the introduction of these secondary parasites 

 must be guarded against when introducing beneficial insects. The 

 newly introduced parasite may also be attacked by secondary ones 

 indigenous in the locality, which had as their original host species of 

 the same genus as the parasite introduced. This has occurred in the 

 case of Ajxintelesfulvipes, introduced against the gipsy moth {Lymantria 

 dispar). Tertiary and quaternary parasitism, which are stages of 

 parasitism beyond that of secondary, are not of common occurrence. 

 The latter has been recorded, but is probably accidental. The former 

 occurs in the case of the Eulophid, Asecodes aJbitarsis, which generally 

 breeds upon Dihrachys houclieaniis, which is a true secondary parasite. 



Super-parasitism is defined, according to Fiske, as the form of 

 symbiosis resulting when any individual host is attacked by two or 

 more species of primary parasites or by one species more than once, 

 though the author considers that this term should be restricted to 

 cases where there is a superabundance of parasites of a single species, 

 using the term multiple parasitism for cases where the same individual 

 host is infested simultaneously with the young of two or more 

 difierent species of primary parasites. 



QuAYLE (H. J.). Dispersion of Scale Insects by the Wind. — Jl. Econ. 

 Entom., Concord, ix, no. 5, October 1916, pp. 486-492, 1 fig. 



That young individuals of the black scale {Saissetia oleae) are carried 

 by the wind has been proved by a series of experiments "with tanglefoot 

 sheets put out on 28th June 1915, when in difierent situations and at 

 distances ranging from 10-450 feet from infested trees, a total of 7,262 

 scales were captured. The young individuals of the red scale, Chrysom- 

 phalus aumntii, were captured in a similar manner at distances ranging 

 from 6-150 feet from infested trees. As a proof that living as well as 

 dead scales may be carried by the wind, a four acre grape-fruit orchard 

 was fumigated in 1914. In April 1915, no black scale could be found, 

 but by midsummer young individuals were present, which must have 

 come from neighbouring infested trees growing on the west, south 

 and east sides of the orchard. A diagrammatic table shows that the 

 spread of the scale followed the direction of the prevailing "^-ind. This 

 was corroborated by another series of experiments performed with 

 tanglefoot sheets exposed on barren ground at varying distances from 

 infested branches removed from the trees. In the case of S. oleae 

 dispersion by the wind occurs chiefly while the young are emerg- 



