506 



about 20 days. When the locusts are in flight, the adults of S. caridei 

 can be seen following them like a cloud. It is said that the locust 

 recognises its enemy and tries to evade it, frequently falling to the 

 ground in its attempts to escape. 



The other enemies of Schistocerca jjarcmensis are reviewed, all of 

 which, for various reasons, are less adapted for use in control than 

 S. airidei. Bacteria can be successfully used only under certain 

 conditions : the coccobacillus of d'Herelle [Coccobacillus acridiorum], 

 for example, while very efficacious in the laboratory at 77° F., is said ta 

 be absolutely useless under the hot sun of Santa Fe or on a soil heated 

 to 132° F. AVhile, therefore, these methods are useful as accessory 

 means of control when used under expert direction in certain 

 years and under favourable climatic conditions, they cannot be 

 counted on as reliable. Sarcojphaga caridei, on the other hand, is. 

 harmless to agriculture, animals and man, has great powers of 

 reproduction and resistance, and is adaptable to various regions and 

 climates, including all those districts in which Schistocerca 'paranensis- 

 occurs in Argentina. 



The method of collection and propagation is as follows. Parasitised 

 larvae of S. 'paranensis are collected and stored on wooden or cement, 

 floors. When the mature larvae of Sarcophaga caridei emerge from 

 their hosts, they are unable to enter the ground to pupate and the 

 pupae can then be collected and transported to those districts where 

 locusts are troublesome. The author emphasises the economy and 

 utility of this method and hopes that its adoption will not be delayed 

 with disastrous results, as happened in the case of Prospaltella berlesei,, 

 which is now used with marked success against Aulacaspis {Diaspis), 

 pentagona. 



Brethes (J.). Consideraciones sobre el Parasitismo en el Bicho de. 

 Cesto {Oeceticus platensis, Berg.). [A Consideration of the Parasi- 

 tism of the Bagworm, Oeceticus platensis, Berg.] — AnaJes Soc. 

 Rural Argentina, Buenos Aires, li, no. 4, June 1917, pp. 339-34:0. 

 [Received 12th September 1917.] 



From the examination of a collection of bagworms in the vicinity 

 of Buenos Aires it is concluded that 80 per cent, of Oeceticus platensis- 

 occurring in Argentina fail to reach maturity owing to being parasitised 

 by various enemies. These include the Ichneumonids, Pimpla tomyris,. 

 Schr., P. oeceticola, Brethes, P. holmbergi, Brethes, Allocota bruchi,. 

 Brethes, PJiobefes bruchi, Brethes, and the Chalcidids, Spilochalcis bergi,, 

 Kirby, and Tetrastichus p)laiensis, Brethes. All these have been 

 collected in the vicinity of Buenos Aires, while the fly, Phorocera 

 xanthiira, was obtained from Mendoza. It is suggested that the- 

 remaining number of bagworms that are able to complete a normal 

 development might be controlled by the introduction of further 

 parasites from other parts. In Cordoba, for example, bagworms are 

 not sufficiently numerous to constitute a pest, the probability being 

 that they are held in check by their insect parasites, which, however, 

 are distinct from those occurring in Buenos Aires, none of those found 

 in the one region apparently occurring in the other. Perissocentrus^ 

 caridei, a new species from this locality, can for example be easily 

 distinguished from P. argentinae, Crawf, Further parasites from this. 



