Sex Determination in Phylloxerans and Aphids 201 
counted for the failure of the division of the chromosomes in the 
first division of the bee, and, worse still, it fails completely to show 
how in the wasp the first division is a reducing division since all 
the chromosomes are retained. Whatever evidence the future has 
in store for us concerning the second division of the spermatocytes, 
the failure of the first division seems in all probability to be con- 
nected with the presence in the male of the reduced number of 
chromosomes. 
Schleip finds for the ant, Formica sanguinea, that two polar 
bodies are given off from the egg as Henking had previously de- 
termined for another species, Lasius. “The reduced number, 24, 
of chromosomes, appears in all eggs. Two polar bodies are 
formed, and into each 24 chromosomes are ejected. The female 
pronucleus contains still 24 chromosomes. After fertilization 
about 48 chromosomes can be counted, and the inference is plain 
that the reduced number, 24, is brought in by the sperm. These 
facts fit in with the results for the bee and go to show, taken in 
connection with the recent results on spermatogenesis, that the 
male contains the reduced number of chromosomes, the female 
the double number. 
Lams has also found in another ant, Campodinotus herculaneus, 
that the first spermatocyte division is abortive and the second 
normal. No evidence of a lagging chromosome is to be found in 
the admirable side view of spindles given by Lams. 
It has been generally taken for granted that in the ant as in the 
bee unfertilized eggs produce only males and this view has the 
support of observations by Forel, Lubbock and Field. On the 
other hand Wheeler*® has recently drawn attention to other obser- 
vations showing conclusively that the unfertilized egg in certain 
species may produce females. Tanner obtained workers of Atta 
cephotes from an artificial nest composed of workers. The same 
nest produced numerous males also. Reichenbach obtained large 
numbers of workers of Lasius niger from the eggs of workers 
laid in an artificial nest. Males, too, appeared synchronously with 
their appearance in nature. Mrs. Comstock has also obtained 
15 Wheeler, W. M. The Origin of Female and Worker Ants from the Eggs of Parthenogenetic Workers, 
Science, xviii, December, 1903. 
