102 SEVENTEENTH Report STATE ENTOMOLOGIST OF MINNESOTA—1918 
white clover, but it gave no attention to either. Then it was given 
the red clover again with the same results as before. Altho no egg 
was found when the red clover seeds were dissected immediately 
afterward, the behavior of the insect may be considered as strongly 
supporting the other evidence that the chalcid does not oviposit in the 
seeds of sweet clover or white clover. 
NATURE AND EXTENT OF INJURY 
The damage is done by the larva inside the seed devouring its con- 
tents. In most cases this work is so thoroly done that nothing is left 
but the seed coat. An affected seed still containing the insect can 
usually be distinguished from a healthy seed by its dull brown color, 
lack of luster and slightly shriveled or otherwise misshapen condition. 
Moreover an infested seed can be crushed in the fingers while a sound 
seed is hard. A seed from which the insect has emerged is an empty 
shell with a hole in one side through which the adult made its escape. If 
the adult emerges before the seed has been hulled or shattered out of 
its receptacle, a hole may also be made in the latter. In the case of 
emergence from a clover seed a hole will frequently be made through 
the side of the corolla. An adult coming from an alfalfa seed will 
make a hole in the pod directly over that in the seed. The plant itself 
is apparently not injured and the only way to detect the presence of the 
larva is by examination of the seed. 
While the damage to the seed crop by the depredation of this pest 
has been very great, in many cases the growers have either not suspected 
their loss or, when they have, being ignorant of the real cause have at- 
tributed the shortage in yield to weather or soil conditions or to the 
work of the midge. Empty seed coats from which the adults have 
emerged are blown out with the chaff from the huller and thus escape 
notice. Many of the seeds containing larvae, being as heavy as normal 
seeds, may go into the bins with the latter, so that if the owner does 
not recognize them, as many do not, he will overestimate the value of 
the yield. 
Counts made of infested seeds give some striking results. Fol- 
som (1909), writing of conditions in Illinois, states that out of 49 
clover seeds taken at random, 14 were found to be injured. Titus 
(1904) reports injury to the extent of 40 to 83 per cent with an average 
of 50 per cent to the head. Presumably his data were secured near 
Washington, D. C. Concerning the extent of injury to the alfalfa seed 
crop, Urbahns (1914) says that in samples collected from different 
localities, 10 to 30 per cent of the seeds of early crops and 20 to 70 
