340 



Early in May they migrate to the fields, depositing eggs in clusters 

 in the soil for about six weeks, these hatching in 15-18 days. The 

 larvae are comparatively active, though fragile and highly susceptible 

 to excessive moisture. The larval stage lasts 23-28 da3''s, the pupal 

 stage 10-15 days, the total life-cycle being 57-65 days. There is one 

 generation a year. In 1921 larvae were found in June and July, and 

 pupae from the end of June to the end of August. The adults began 

 to emerge about the end of July. The maximum emergence in 1920 

 was in the last week in August and the first days of September, but in 

 1921 it was about the 25th July. The adults are active and are seen 

 in great numbers in sunny weather. Flight occurs in spring, when 

 they leave their winter quarters and go to the crops, and again towards 

 the end of the season when the crop has been pulled. During active 

 feeding flight rarely occurs ; the beetles hide beneath flax leaves 

 when not feeding. 



Natural enemies include various birds. Gravid females are devoured 

 by a Carabid, Bembidium lampros, which possibly also eats the eggs. 

 The adults are also attacked by larval mites, Trombidium sp. ; one 

 specimen found was believed to be a larval form of Rhyncholopims 

 phalangeoides. The larvae and pupae were attacked by Tyroglyphid 

 mites in captivity, but their presence was probably accidental. They 

 are apparently not attacked by Hymenopterous or internal parasites. 



Remedial measures include the production of strong, vigorous 

 growing young shoots by using suitable seed, manure and cultivation. 

 Very early sowing is not desirable in districts where the beetle is preva- 

 lent. Small areas sown a week earlier than the main crop will serve as 

 trap crops. Beetles may be destroyed by sweeping over seedlings 

 in bright sunlight with a sack or light white board coated with tangle- 

 foot or similar material. Trap plots should be thoroughly cultivated 

 in late June to kill any eggs laid in May and June. Attacked 

 seedlings may be stimulated by applying light dressings, one of which 

 has already been noticed [R.A.E., A, ix, 447], and experiments with 

 others are described, though they have afforded no obvious protection. 



Brethes (J.). El Bicho de Cesto [Oeceticus kirbyi var. platensis. 

 Berg). Campaiia 1920-21. Dos nuevos Parasites. [TheBagworm. 

 Work done in 1920-21. Two new Parasites.] — Inst. Biol. Soc. 

 Rural Argentina, Buenos Aires, 28 pp., 23 figs., 1 coloured plate, 

 1 map. [Received 28th April 1922.] 



As a result of the examination of a large amount of material the 

 author states that the Argentine bagworm, hitherto known as Oeceticus 

 platensis. Berg, is not specifically distinct from 0. kirbyi, of which 

 he proposes to treat it as a variety. The smaller size, lighter colour 

 and other differences that increase towards the south are simply due 

 to the climate. Much of the information given has already been 

 noticed [R.A.E., A, vi, 315, 517; viii, 298]. In the campaign of 

 1920-21 the Tachinid parasite, Parexorista caridei, Brethes, was 

 utilised on a larger scale than before, more than 300 lots of parasitised 

 material being sent out, and the fly is now established throughout 

 the province of Buenos Aires, except on a part of the coast. Though 

 less important, Tetrastichus platensis, Brethes, destroys large numbers 

 of bagworms, especially when they are still small. An Acarid, 

 Pediculoides ventricosus, Newp., comes next in order of importance ; 

 its action is chiefly noticeable when the bags contain the eggs of the 

 moth. The twelve other parasites of this moth that are already known 



