464 Journal of the Department of Agriculture. — Nov., 1922. 



<l;irl< and iliick, while (lie opening- ;il tlic " Itulioii" is closer and 

 longer than in the c/iloro/zj/ija iiui^'^'ul . The jmpariuiii of this fly, loo, 

 can be easily rec()<j;Hi>ce(l, ()\vin<^- io the tubercles which remain when 

 the n)ag'got ])upates. \\ may not be out of place heie (o remark' 

 that when fly maggots puj)ate, they do not form a cocoon, noi- shed 

 the larval skin, as is the case with bulteiflies and moths. When 

 ready to pupate, the magg-ot contracts, becomes barrel-shaped, and 

 loujided at each end. The larval skin, contracted in this way, 

 becomes hard and brown, forming- what is termed the pupariuni, 

 and the true pupa is formed within it. When the adult fly is ready 

 io emerge, a cap on the head end of the puj)arium is forced off, and 

 tiie fly draws itself out. When first enierged, the fly is pale-coloured 

 and the wing's are crun)pled up, but the wings soon grow out to 

 their full size, and in a short while the fly assumes its proper 

 colouration. 



The Green-bottle Blow-fly. 

 Lucilia sericota, Meig. 



Lucilia serivata, Meig., is a typical " green-bottle " fly, and can 

 easily be distinguished from the two species of Pycnosoma by its 

 plain rather darkish shining green colour, and by the fact that it is 

 somewhat bristly. This species also has a much more slender appear- 

 ance than the other two. Another species of Lticilia, L. 

 argyrocephala, resembles this species very much, but is more bristly. 

 It is faiily common in the Transvaal, but the writer has not yet 

 observed it m the eastern (Jape Province, nor has it been recorded 

 from wool. Another fly that might be mistaken for Lucilia sericata 

 is PyreUia cyanca. This fly is very like the Lucilia in size and 

 shape, and when alive is also of a plain shining but perhaps some- 

 what lighter green. When it is dead its thorax becomes a deep 

 shining blue, while the abdo)nen remains green. This PyreUia has 

 not been recorded as a pest on sheep, and it probably breeds in 

 excreta; it occurs very commonly resting and feeding on ox droj)- 

 })ings, and is found all over the Union. 



])uring the present summer (lO'Jl-'J'-J) Lncilid .sericata has not 

 been found to any large extent in wool in the coastal region; in 

 faci, not more than one or two per cent, of the flies reared from wool 

 were of this kind. It is, however, common in the town of East 

 Jiondon. It has been reared in large numbers from meat exposed 

 expeiinientally, and it can be seen in numbers in butchers' shops, 

 where it deposits its eggs on the meat exposed for sale. Although 

 not of importance as a sheep pest near the coast, this species is the 

 only one reared from wool leceived from up-country — the Orange 

 Fi'ee State — up to now, neithei- of the Pyctiosomas being present. 

 Just what conditions control these pests can only be conjectured at 

 ])resent, but more detailed future observations may throw some 

 interesting light on the subject. 



The maggot of this species is somewhat similar to that of 

 Pycnosovia ch.loropyga, but is not so robust. An examination of 

 the posterior stigmata (Fig. 4) will quickly enable one to distinguish 

 it. The stigmata are not so heavily chitinized and darkened, and 

 are therefore not so conspicuous; the peiitreme is quite narrow, and 



