204 A Study of the Capsid Bngsfomul on Apple Trees 



9. THE ENEMIES OF CAPSIDS. 



We gave very little attention to this side of the subject but we never 

 found any insect attacking capsids. We found a cimicid Anthocoris 

 sylvestris sucking the dead bodies of capsids at various stages and we 

 also saw several species of capsid sucking the dead body of the same or 

 different species. It is possible that Anthocoris sylvestris and also some 

 species of capsids, e.g. Psallus ambiguus, are capable of killing live capsids, 

 but we have never observed them doing so. 



The young capsids are so active except at moulting that they would 

 probably escape from such enemies as those which attack aphis. We 

 found dead capsids on the trees and on healthy shoots in cages but we 

 were unable to assign a causal organism. 



10. THE FOOD OF APPLE-DWELLING CAPSIDS. 



Both the nymphs and adults of Plesiocoris rugicollis live mainly on 

 the juices of the leaves, stem and fruit of various species of plants, but 

 they have been seen sucking dead individuals of the same or another 

 species. Where they suck another bug a blackish mark is formed. This 

 is also true of Psallus ambiguus, Orthotyhis marginalis, Atractotomus mali 

 and larvae of Phytocoris ulmi. Atractotomus mali has been recorded as 

 attacking caterpillars of Hyponomeuta (13, 20), and in one case we found 

 a large number of adults near a nest of these caterpillars. Such large 

 numbers were never found together in any other place. 



Psallus ambiguus feeds on plant juices but it can live for several weeks 



ou dried twigs on which nymphs and adults of Psylla mali and young 



forms of Tetranychus sp. were present. No definite observations were 



made as to its carnivorous nature, but Rymer Roberts writes that " a 



nymph of Psallus ambiguus fed on Aphis avenae and also on two syrphid 



eggs." 



II. REFERENCES. 



1. AwATi, p. R. Proc. Zool. Soc. Lond. 1914, p. 685. 



2. Brittain, W. H. The Canadian Horticulture. Dec. 1915 



3. Rev. App. Ento. Dec. 1916. 



4. Caesar. Ent. Soc. Ontario, 1912, p. 102. 



5. CoLLiNGE. Journal Eco. Biol. vol. vir. p. 64. 



6. Crosby. Cornell Uni. Bull. No. 291, 1911. 



7. Crosby and Leonard. Cornell Uni. Bull. No. 364, 1911. Give a long list of 



literature on Capsidae. 



8. Douglas and Scott. A Catalogiie of British Hemiptera, 1876. 



9. Faxleri, C. F. Monographia cimicum sveciae, 1818, p. 76. 



10. FiEBER, F. X. Die Europdischen Hemiptera Halbfliigler, 1861, p. 272. 



11. Fryer, J. C. F. Preliminary notes on the damage of apples by Capsid Bugs. 



The Annals of App. Biol. vol. i. no. 2, 1914. 



12. Fryer, J. C. F. Journal Board of Agriculture, Jan. 1916. 



