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the aphides so that few are left to hibernate and produce other gen- 
erations of the pest the following year. 
The value of these natural enemies against aphides is such that 
entomologists frequently advise the employment of remedies only 
when the enemies are not present in abundance. The possible utiliza- 
tion of natural enemies in the field will be considered on pages 15 and 
16 of this circular. In tobacco fumigation, which will presently be 
considered, we have an almost ideal remedy, for the reason that, while 
aphides are all destroyed, a considerable proportion of the ladybirds 
and other hardy beneficial insects, which are practically always present 
on the infested vines, survive this treatment. 
Fig. 4.—A syrphus-fly (Syrphus ribesii): a, fly; b, lateral view of head; ec, larva or active immature 
form; d, anal spiracles; e, thoracic spiracle of same. All much enlarged (original). 
METHODS OF CONTROL. 
The severe losses occasioned by the melon aphis in its seasons of 
greatest destructiveness could be largely mitigated and in many cases 
almost entirely prevented if the employment of methods for its con- 
trol were begun upon the /nsect’s first appearance. For its successful 
treatment it is necessary to keep constantly in mind several of the 
facts that have already been given more in detail. In ordinary sea- 
sons the species is controlled by the combined operation of natural 
elements and insect enemies, but at times when the weather is unfa- 
vorable to the development of these enemies the grower should be on 
the alert. The presence of the aphides is often not detected until they 
are numerous, and even then they are not apt to be noticed unless the 
lower surface of the leaves be examined. 
All things considered, the most satisfactory way of controlling this 
insect is by fumigation. As an aid, however, cultural methods are 
necessary. In the South spraying with kerosene and other emulsions 
is preferred to the bisulfid of carbon method, and tobacco is now much 
used, especially in Texas. The encouragement of natural enemies 
gives promise of success. 
