IOWA ACADEMY OF SCIENCES. 
91 
Schizoneura panicola is permanently root- inhabiting unless a 
dimorphic form, and occurs on roots of weeds, and also on corn 
and sorghum.^ 
Both forms are of economic importance, and may at times 
cause serious injuries. 
The aerial form of corn! may be destroyed by burning the 
Dogwood bushes in late autumn, winter or early spring. 
The panicola form may be prevented from injury to corn or 
sorghum by a rotation of crops and by thorough cultivation. 
EXPLANATION OP FIGURES OP VENATION OP SCHIZONEURCE 
PROM GRASS ROOTS. 
1. Schizoneura corni, from roots of Andropogon furcatus, (typi- 
cal venation of S. corni on Cornus leaves.) 
2. Sell, corni. From roots of Setaria, (specimen colonized 
on cornus in autumn of 1889, shows typical corni venation.) 
3. Scldz. corni, var. panicola. Thos. From roots of Seta- 
ria viridis, June 24, 1893. Typical venation for the pianicola 
form, but third discordial is forked a little nearer the base than 
in average specimens. 
4. Schiz. corni, var. panicola. Thos. From roots of Seta- 
ria glauca, July 3, 1893. (Differs from No. 3 in point of furca- 
tion of third discoidal.) 
5. Schiz. corni, var. panicola. Thos. From roots of Seta- 
ria glauca. Sept. 25, 1893. (Shows variation in point of origin 
of discoidals, all three starting close together.) 
6. Schiz. corni, var. panicola. Thos. From roots of corn, 
Norway, Iowa, Oct. 13, 1891. 
7 and 7^. Schiz. corni, var. pcmicolu (?). From roots of 
Panicum crus galli, autumn of 1892. (Showing variations from 
normal venation. The costa of lower figure was probably dis- 
torted slightly in mounting.) 
In 1 and 2 the veins are drawn with double lines, as they 
were too robust to represent correctly by single line. 
* The apparent failure to find S. corni on perennial grasses should not be taken as 
conclusive that there is another set of food plants besides the perennial grasses and 
cornus. As already stated, the scarcity of this species made it difficult to locate them. 
Not over 500 specimens were seen during the whole spring. When these were scattered 
by the winds at the time of migration, what few were picked up by the ants would still 
be harder to find. The work was given up after July 15. 
