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Dipterous Larvae 
Cynomyia cadaverina Desv. (Plate XIY, figs. 3 and 4.) 
The stigmata of this larva appear also as two fan-shaped plates. 
Although the actual size and shape of each plate, and the distance 
between them, are almost the same as in Lucilia caesar, there are wide 
differences which distinguish the two genera. The “ ring ” in C. 
cadaverina is rather more heavily chitinised, the “ button ” is larger, 
and more densely surrounded with chitin, while the angles which the 
slits make to the median sagittal axis of the larva are very much 
greater. 
Moreover there is an essential difference in the arrangements of the 
bars which cross the slits. These instead of running from the extreme 
edge of the one slit to the extreme edge of the other, as in Lucilia caesar, 
start a little distance from one side of the edge and run over to an equal 
distance beyond the other edge, tending to arch over the gap to some 
extent (fig. 4). This arrangement gives a characteristic appearance 
not found in any of the other genera that have been examined. The 
breadth of the stigmal plate in this case is from 0’52-0'56 mm. and the 
distance between the “ buttons ” from 0’48-0 - 53 mm. 
Calliphora vomitoria Linn. (Plate XY, figs. 5 and 6.) 
In the larva of this fly the stigmata are considerably larger than those 
of the larvae of the preceding two genera, being from 0'60-0‘68 mm. 
in breadth, with the distance between the “ button ” of the one plate 
and the “ button ” of the other ranging from 0‘56 mm.-0'64 mm. 
The “ ring ” is very heavily chitinised, and the “ button ” well marked. 
The angles of the slits are very much the same as in the case of Lucilia 
caesar, but here again the characteristic difference of the genus is found 
in the bars that cross them. These are far more numerous than in the 
other examples described above, and though in this case they run from 
the extreme edge of the one side to the extreme edge of the other, as 
in Lucilia caesar, they are nevertheless only about half the breadth, and 
from 20-24 in number for each slit. 
Sarcophaga sarraceniae ? Riley. (Text-fig. 2 b.) 
In the stigmata of this species we meet several remarkably different 
features. The most striking is perhaps the position of the slits. Instead 
of making wide angles with one another, they approach a parallel 
arrangement, and what is still more noticeable, are arranged so that 
