NATURAL ENEMIES. 
The diagram (fig. 25) shows the relation of the three generations of 
parasites as observed in the breeding cages to the time of oviposition 
and the time of hatching of the host eggs. With the data in hand it 
is not possible to determine the period covered by each generation. 
The records only show the appearance of the first adults for the three 
generations. A few conclusions can, however, be drawn from the above 
diagram. Adult parasites must have existed in vineyards at the 
time of earliest oviposition of the grape root-worm. Adults producing 
the second generation appeared before the greater portion of the root- 
worm eggs had hatched, and since eggs could become parasitized 
within two days of hatching, the second generation is apt to infest 
more eggs than either the first or the third generation. In fact, the 
third generation appeared so late that it only reached a very few 
belated eggs. 
Fidiobia flavipes is an important factor in the control of the grape 
root-worm. Professor Webster, who for several years studied the 
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Fig. 25.— Diagram showing the relation between the three generations of the Fidiobia parasite and 
the relative occurrence of eggs of the grape root- worm at North East, Pa., during 1909. (Original.) 
grape root-worm in Ohio, reported in 1896 that the decrease in num- 
bers of the beetle was largely due to this and other parasites. Though 
the data on hand for North East, Pa., for the years 1907, 190S, and 
1909 are not sufficient to show any increase in occurrence, it is our 
impression, from extensive observations, that the insect is becoming 
more and more numerous. 
A DIPTEROUS PARASITE. 
Along with Fidiobia flavipes there occurs another grape root-worm 
egg parasite (fig. 26), which is at present only known in the larval 
stage. It is supposed to be a dipterous insect, in view of ihs resem- 
blance of the larva to dipterous forms. It was lirst observed by the 
senior author and Mr. P. K. Jones, of the Bureau of Entomology, who 
in 1907, at North East, Pa., collected several parasitized egg clusters. 
