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Guiana) ; parasites of the larva : Iphiaulax medianus, Cam., 

 Crenmops parvifasciatus, Cam., Mesostenoideus sp., (all from Br. 

 Guiana), Ophion matintii (Mauritius)*, Lioderma i-dentatum (Br. 

 Guiana), Chaidiognaihus marginaUis and Drasterius elegans 

 (Louisiana). It is suggested that a large importation of larval para- 

 sites from British Guiana would be very useful, if combined with a 

 serious attempt to propagate the native parasite on a large scale. 



The parasites of Chilo infuscatellus, Sn. (the yellow tip borer) are 

 for the most part the same as those of Diatraea. According to 

 Zehntner and van Deventer, P. beneficiens, Zehnt., attacks the eggs 

 and the author's own observations prove that T. australicum is also 

 an important egg-parasite. Neither T. minutum nor T. nanuni have as 

 yet been bred from eggs of C. infuscatellus in Java, but it is probable 

 that they are also egg-parasites. The larvae are parasitised to a small 

 extent by an undescribed Braconid and a Tachinid. 



No important parasites of Scirpophaga intacta, Sn. (the white tip 

 borer) have been found, except P. beneficiens, which is said to infect 

 as much as 50 per cent. Zehntner described an Elasmus and a Macro- 

 centrus as occasionally parasitising the larvae, and early in 1914 an 

 Ichneumonid parasite of the pupa was discovered, which is still under 

 investigation. 



Until recently, no parasites of Olethreutes scJiistaceana were known, 

 but in 1913 it was discovered that T. australicum and T. nanuni were 

 to be regarded to a limited extent as egg- parasites. T. minutum has 

 not yet been obtained from the eggs and no parasite of the larvae is 

 as yet known in Java. 



Diatraea has three maxima of appearance in the year, viz. the end 

 of January, the beginning of April and the middle of June, the largest 

 outbreaks occurring from May to July, and considering the short life 

 of the pest, and the favourable conditions which the chmate of Java 

 affords for its development, it is at least probable that the fluctuations 

 in its numbers are directly due to the parasites. When the number 

 of eggs is small, the proportion parasitised is also small, and it is only 

 when the eggs become very numerous that 60 or 80 per cent, are 

 attacked, and the shoi-fc hfe of the parasite enables the pest to recover 

 itself and again become numerous. It is probable that enormous 

 numbers of parasites die in these intervals, and it is therefore highly 

 desirable to maintain large supphes of Phanurus to act as reserves at 

 the critical periods. The author is of opinion that the percentage of 

 lost and destroyed parasites, after they are set free, may be very high, 

 and the results of eight experiments do not show any very clear or 

 constant relation between the release of parasites and the percentage 

 of attacked eggs. The best possible use to make of the parasites is to 

 release them on quite young plantations, so that they may keep down 

 the pests from the start ; the necessary material can always be 

 obtained from the older cane-fields. 



The source of infection of new plantations is undoubtedly the older 

 cane-fields. The terms of lease of cane-land in Java require that 

 one-third of the area shall be planted with sugar-cane every year, and 

 thus young cane is often growing alongside cane waiting to be cut, 



[*The inclusion of this species is probably due to a record published by M. 

 de Charmoy, but specimens received from him under this name proved to be 

 Henicospilus antancarus, Mori. — Ed. J 



