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Though each female is the potential ancestor of 6,750,000 indi- 

 viduals in 4 years, only two caterpillars are found on the average on 

 each tree. Cold weather early in the year destroys many moths before 

 they have oviposited or renders them incapable of doing so; heavy 

 rain may also prove fatal. The young caterpillars are very sensitive 

 to cold and heavy rain, and the latter may wash older caterpillars from 

 the trees. Prolonged rain may either drown the pupae sheltering 

 under leaves and other debris on the ground, or may lead to their death 

 through the heat evolved when the soaked material is afterwards sub- 

 jected to the influence of warm, dry weather, or again may favour 

 the growth of fungi injurious to them. Lack of food leads to the 

 death of many caterpillars. Natural enemies of the adults include 

 bats and many birds, the latter also feeding on the caterpillars. 

 Among the mammals that destroy the pupae wild pigs are the most 

 important and they are so effective that the use of domestic pigs has 

 been recommended for this purpose. Stoats, weasels and Miis sylva- 

 ticus are other destroyers of the pupae. These mammalian enemies 

 however also destroy the parasites of the pupae. Both caterpillars 

 and pupae of P. flammea are preyed upon by several beetles and 

 their larvae. A wasp, Ammojiliila sabulosa, paralyses the caterpillars 

 prior to ovipositing m them. Parasitic insect enemies play a decisive 

 part in checking an outbreak, but may take 2 or even 3 years to do so. 



Smits van Burgst believes that there is no insect with more para- 

 sitic enemies belonging to its class than P. flammea and has submit- 

 ted a Hst of 33 Hymenopterous species to which the author adds a 

 further 3. These are: — IcJineiimoncomita,tor,h., I. trilineatas, Gvae\., 

 I. scutellator, Grv., /. nigritarius, Grv., I. fabricator, F., I. annulator, 

 F., I. pallidifrons, Grv., I. dumeticola, Grv., /. derogator, Wesm., 

 I. bilunulatiis, Grv., /. molitorius, Grv., I. gradarius, Wesm., I. equita- 

 torius, Panz., I. tristis, Grv., I. nigrocyaneus. Grv., I. pachymeius, 

 Ratz., Microcryptus perspicillator, Grv., M. nrrogafis, Grv., Ciyptus 

 cyanalor, Grv., C. tarsoleucus, Schr., C. sponsor, ¥., C. dianae, Grv., 

 Pimpla instigator, F., Euceros crassicornis, Grv., Henicospilus rami- 

 dulus, L., H. merdarius, Grv., Exochilum circumflexum, L., Heteropelma 

 calcarator, Wesm., Anomalon biguftatum, Grv., Banchus com.pressus, F., 

 B. pictus, F., B. femoralis, Ths., B. monileattis, Grv., Mesochorus 

 brevipetiolatus, R.atz., Meteorus scutellator, Nees, and M. albiditarsis, 

 Curtis. It is probable that there are still other Hymenopterous para- 

 sites. Of these the Braconid, Meteortis albiditarsis, and Ichneumon 

 pachyinerus appear to have been very effective in 1919. With regard to 

 these two parasites Smits van Burgst states that the latter has two 

 generations a year and must have another host besides P. flammea, 

 which has one brood only, while M. albiditarsis has one generation and 

 therefore needs no other host. Next to the Hymenopterous parasites in 

 importance come Diptera such as Tachinids, Dexiids, and Sarcophagids. 

 It IS recorded that an outbreak of P. flammea in 1845 was checked by 

 a parasitic fly, probably Tachina (Nemaraea) glabrata. Bacteria and 

 fungi also aid in checking the pine moth, and epidemics due to these 

 sometimes cause a rapid reduction in infestation. The author observed 

 one instance where Empusa aulicae stamped out a local infestation 

 in about a fortnight. This fungus and Botrytis bassiana were active 

 in 1919. Polyhedral disease, formerly confused with flacherie, is 

 another factor in checking P. flammea. 



