950 
Journal of Agricultural Research voi. xxvn, no. 12 
However, the movement Baher observed may have been the mechanical 
straightening of the dead larvae due to their absorption of water. Byars 6 
proved that larvae may live within the galls for at least eight years. He 
examined the contents of galls from various countries and secured the 
data shown in Table XIX. 
Table XIX .—Reactivation of larvae from galls received from various countries 
Source. 
Year 
re¬ 
ceived. 
Date 
examined. 
Age. 
Per¬ 
centage 
alive. 
1914 
1912 
Apr. ti, 1918 
.do. 
Years. 
4 
50-85 
Russia....... 
6 
50-75 
China..... 
1911 
1910 
1910 
.do. 
7 
1- 2 
Turkestan.... . . . .. . 
.do. 
8 
10-15 
0 
China... 
Mar. 26, 1918 
8 
9 
These figures indicate that the larvae in the galls gradually die in 
the course of a few years. This grain, however, at some time or other 
may have been exposed to unfavorable conditions, such as high tempera¬ 
tures, and this would account for the small percentage of larvae found 
alive in the galls after eight years. Most investigators believe that they 
remain alive for a longer period. 
Outside of the protective galls the larvae may exist either in a dried 
dormant condition much as when within the galls, or in an active, free- 
living condition in moist soil or between the leaf sheaths of plants. In 
the former state they remain capable of resuscitation after a considerable 
period, if kept dry and at a low or moderate temperature. The writer 
has revived larvae from galls that had been ground four years previously 
and kept in a glass jar in the laboratory. 
DESICCATION 
The larvae may be killed by such extreme desiccation as obtains in an 
ordinary desiccator containing calcium chlorid and sulphuric acid. This 
is especially true of those larvae which have been in a free-living state 
for some time. The writer placed larvae from galls and from wheat 
and rye seedlings in two series of watch glasses. These were placed in 
a desiccator and at regular intervals water was added to one of the watch 
glasses from each series in an attempt to resuscitate the larvae. Those 
taken from between the leaf sheaths of seedlings showed no indication 
of reviving in water after having been in the desiccator for two weeks. 
Those taken directly from the galls, however, were revived in water 
after more than two months of desiccation. 
In an active, free-living condition the larvae can retain life for a 
considerable period. In sterile, distilled water they remained active for 
nearly five months. In infested soil and in an ectoparasitic state in 
plants larvae may live outside the galls for at least nine months. For 
instance, when wheat is harvested in June many galls fall to the ground. 
The larvae undoubtedly escape from these within a month. If clean 
seed is sown on this infested soil in October plants will be found with 
numerous larvae between the leaf sheaths in the following April or May. 
8 Unpublished data. 
