452 Journal of the JJki'artmkist of Agriculture. — Nov., 1922. 



cephalopharyngeal skeleton (Fig. 6). Just below these hooks is the 

 mouth opening". On each side a short distance behind the anterior 

 end is a process, the anterior spiracle or breathing aperture [Fig. 1 

 (/>)]; these spiracles have the appearance of '"mittens, " the 

 " fingers " varying in number from a few to several. On the last 

 segment of the body is an area [Fig. 5 and Fig. 1 (c)] surrounded 

 by a numl)er of processes. ( )ii this area are the posterior stigmata 

 or spiracles [Fig. 5 (,s) (^)j. This area may be rather sunken, and is 

 sometimes very much so, the upper and lower nuu'giiis coming 

 together like lips. In the full-grown maggot each of the two stigmata 

 consists of a dark more or less thickened ring, the peritreme [Figs. 

 2, 3, and 4 (jj)]. On or just within the peritreme is another structure, 

 the so-called " button " [Fig. 4 (h)], the " buttons " on each spiracle 

 being opposite each other; sometimes the peritreme is broken in the 

 region of the " button." Within the peritreme are the slits [Figs. 

 2, 3, and 4 (s)] through which air is taken. These slits ai'e invari- 

 ably three in number in the full-grown maggot, and in those vmder 

 discussion are more or less straight and sub-parallel (Figs. 2 and 3), 

 while in the house-fly, for instance, they are sinuous [Fig. 4 (.f)]. 

 J']ach slit is crossed by a numl)er of more or less irregular bars wliicli 

 form a grating. 



The following are a few notes on the flies that have l)een ])i<m1 

 from wool and tioni dead slicep during the present sunimei-. 



The TiEssKH Hm I'.-noi ri.i'. lii.ow-FLv. 



P !li-ii()S(iiiiii c/i l<n<//ij///<i , Wied. 



This fly appears to be the one that is primarily responsible for 

 blowing M'ool in the Border Districts of the Cape Province. It is 

 more prevalent in the early part of summer, when it is found to 

 the extent of about 80 per cent, of the flies bred fiom wool and 

 from dead sheep. In East liondon it has been reared from exposed 

 meat, but not to such a large extent. 



In appearance it very much resembles the common blue-bottle 

 fly, Fycnosoma raarginale, Wied., but is smaller, and can readily 

 be distinguished by the markings on the front part of the thorax, 

 these being like two L's back to back over a W, thus: H^- I'b^ 

 flies vary much in size, some individuals bred from underfed maggots 

 being only a third the normal size. Pycnosomn cldoropyiia, Wied., 

 occurs commonly all over the Union, and has been found by tlie 

 writer indoors during the winter months in Pretoria. 



The maggot (Fig. 1), Avhen full grown, is larger than that of the 

 house-fly, and much more robust. It appears white and smooth, but 

 is provided with bands of small spines [Fig. 1 (r/)]. The posterior 

 stigmata are very prominent, being dark and heavily chitinized. A 

 good idea of a spiracle will be obtained from Fig. 2; the peritreme 

 is dark and fairly broad, Avith quite a wide opening in the region 

 of the "button"; within the peritreme the slits with their adjacent 

 areas practically fill up the whole of the space. The stigmata of this 

 species closely resemble those of the maggot of Fycnosoma alhiceps, 

 but as the maggot of the latter is very distinct, there will be no 

 difficultv in distinguisliing tlie two. 



