108 
Psyche 
[March-June 
were very lively, ran about the jar rapidly and in their efforts 
to escape easily walked over the band of vaseline that was 
spread to prevent their leaving the jar. When they run about 
they curl up the ends of their abdomens very much like rove 
beetles; the young of Parcoblatta pennsylvanica , Blatta orien- 
talis , or Periplaneta americana do not have this peculiar be- 
havior. 
On hatching, the nymphs are black with white bands on two 
abdominal segments; the basal segment and one in the middle. 
Several weeks after hatching I noticed that the first 4 or 5 joints 
of the antennae were also white. A month or six weeks later, 
probably after a moult, the white band on the middle segment 
became broken so that the center third of it was black. I found 
still later that both of the white segments in all nymphs in this 
jar changed to an inconspicuous light brown color while the 
insect itself was still dull black. On that day I was again sur- 
prised to find that in addition to the 4 or 5 segments of white at 
the tip of the antennae there was a white portion covering one- 
fourth of the antennae at its point of attachment. By August 31, 
they had grown to about one-half inch in length, and when a 
moult occurred on November 7, the few that had not died were 
of a light brown color, resembling very much the half-grown 
nymphs of P. americana. 
I do not know if the nymphs I have obtained are pure P. 
fulignosa or hybrids between them and their traveling com- 
panions, P. americana. If the three females of P. fulignosa were 
trapped in New Orleans just before shipping to St. Louis, it is 
likely that they mated with their own species, but if they grew 
up among the americana in the breeding cages of the dealer, 
from whom I obtained them, it is quite likely that they were 
fertilized by the males of americana. Then again, they might 
have been bred in confinement for a number of generations 
with the result that crossings and re-crossings often may have 
occurred. The fact, however, that the few roaches which 
reached middle age became more and more like P. americana 
leads me to believe that the nymphs which Mr. Hebard said 
could easily be mistaken for P. brunnea are not pure stock, but 
are of hybrid origin, mixed with americana for one or more 
generations. 
