116 ENTOMOLOGICAL SOCIETY 
has not once been encountered in connection with our rearings 
of Isosoma from timothy, even where the wheat and timothy 
were growing in the same locality. The principal parasite and 
one that is clearly holding the timothy Isosoma in check in 
some localities, is Syntomaspis lazuella, and where this occurs 
in greatest abundance we almost invariably get few or no 
Isosoma from timothy, while if few parasites occur the reverse 
is the rule. This Syntomaspis also deserves more than a 
passing notice. Its occurrence is peculiar. It may be reared 
in abundance from Isosoma infested rye, but not from simi- 
larly infested wheat, even where the two grains are grown on 
the same farm. I have never got a single individual from 
either wheat or Klymus, though both were badly infested by 
Isosoma, while it was certainly excessively abundant in the 
neighborhood and reared there from both timothy and rye, 
known to contain Isosoma larvae. 
There seems to be an interesting feature of this Syntomaspis 
involving both color and geographical distribution. Specimens 
reared from timothy and other grasses, except Elymus, from 
Virginia, Ohio, Michigan, Indiana, Northern Illinois, North 
Dakota and (the type) West Cliff, Colorado, are metallic green, 
with metallic, more or less blue, abdomens, while those from 
Kentucky, Tennessee, Georgia, Alabama, Mississippi, Texas, 
Oklahoma, and Kansas, are entirely of an indigo blue. Cur- 
iously enough, in southeastern Nebraska and southern Iowa we 
find both colors intermixed. These color differences are more 
marked in fresh specimens. It is possible, of course, but 
hardly probable, that these two colors indicate different species. 
Mr. Ashmead stated that he also had noticed color differences 
in several species of Pteromalidae and Torymidae from blue 
to metallic green. The same difference also occurs in some 
Chrysididae and in some Carabid beetles. Mr. Ashmead also 
stated that he had lately received from Ivan Vassilief , from 
Russia, a species of Isosoma which that gentleman reported 
was parasitic -on Cephus pygmceus in wheat stems. This 
Dr. Ashmead stated was of course only an error of observa- 
tion. 
Dr. Gill called attention to the cases in nature where allied 
species are constant for one species and variable in the other. 
He stated that there were several notable examples among 
the shells. Mr. Schwarz made some remarks on the extreme 
