92 
Psyche 
[April 
of marking was observed and the testes preserved from individuals 
representing these differences. These specimens of Philaenus 
were sent to Mr. Van Duzee at the time, 1912, and identified by 
him as all belonging to the species Philcenus leucophthahnus 
(spumarius) . From a study of Mr. Van Duzee’s Catalogue of 
the Hemiptera, 1917, I find many varieties of P. leucophthalmus 
recorded. The names of some of these are clearly descriptive of 
the somatic characters which were conspicuous in the Woods 
Hole material which I studied cytologically. The chromosome 
group in all these varietal forms was identical, the same situation 
as in the two varieties of Monecphora hicincta. There is there- 
fore cytological evidence for the present systematic classifica- 
tion of the varieties of Philcenus leucophthalmus and of Monec- 
phora hicincta as varieties instead of as separate species. In the 
Cercopidse specific differences seem to be correlated with dif- 
ference in number of chromosomes while varietal differences do 
not seem to be expressed in visible differences of any sort in the 
chrosomomes. 
Those few specimens of the southern banded form of 
Monecphora hicincta at Norridgewock, Maine, raise other interest- 
ing questions, especially as to which was the original form. 
Evidently the banded form was the firs-t one described. If it is 
the older, has the black form arisen from it as a result of suf- 
fusion? If so, what caused the return to the banded condition 
in those few specimens at Norridgewock? Can this be explained 
as a genetic reversion due to the chance recombination of genes? 
On the other hand, the black form may be the original which 
occasionally throws off banded mutants, those once thrown off 
in the south having firmly established themselves, those in 
Norridgewock being recent mutants. These questions are of 
course not to be answered by cytological methods. Experi- 
mental breeding would answer some. The cytologist must 
content himself with establishing these two varieties of Monec- 
phora hicincta as belonging within one species. 
