1903.] PHILLIPS—A REVIEW OF PARTHENOGENESIS. 295 
tera, some of the workers being Réaumur (1738), Pallas (1767), 
Degeer (1771), Kiihn (1775), Schiffermiiller (1776), Schrank (1776 
and 1802), Scriba (1790) and Reutti(1810). v. Siebold was at first 
(1849) inclined to doubt the existence of parthenogenesis in these 
species, but in 1856 published the results of elaborate experiments 
in which it was fully proven. Speyer (1847), Wocke (1853) and 
Reutti (1853) reached similar conclusions, and Leuckart (1858) 
examined the females of So/enodca and found no spermatozoa in 
the seminal receptacle, although there was a micropyle on the egg. 
Hartmann (1871) raised many successive generations of individuals. 
parthenogenetically. 
HeEmiPTERA.—The first to investigate the reproduction of Aphids 
was Leeuwenhoek (1695). He found that the young are pro- 
duced vivaparously and that there are few males, and Réamur 
.(1737) from like observations, on theoretical grounds, held that 
they are protandric. Bonnet (1745), who generally gets the credit 
of having first observed the reproduction of the group, raised nine 
generations of viviparous females in two and one-half months in 
summer, and in the fall males appeared which copulated with the 
females, and eggs were laid which hatched out in the following 
year. Degeer (1773) worked on Lachnus pini and Aphis rose, and 
concluded that sexual individuals could be entirely done away 
with by keeping the insects protected from cold, and in this he 
was confirmed by Kybér (1815), who raised fifty successive genera- 
tions of viviparous individuals in four years. Most of these earlier 
workers thought that the viviparous individuals were larval forms, 
which would afterward develop into the oviparous individuals. 
Similar experiments led Duvau (1825) to believe that the ovipar- 
ous and viviparous individuals are entirely distinct and that they 
never have the power of reproducing in both ways, and later Mor- 
ren (1836), for Aphis persica ; Ratzeburg (1844), for Aphis oblonga, 
and Newport (1847), for Aphis rose, came to similar conclusions. 
Dufour (1841) repeated the experiments of Bounet and referred 
the reproduction of Dzplo/efis galle tinctorte to ‘‘spontaneous or 
equivocal generation, in which impregnation is in no way con- 
cerned.’’ Morren (1836) also believed in this spontaneous genera- 
tion and thought that Aphids are developed in the body of the 
virgin parent : ‘‘ Comme chez quelques entozoaires par individuali- 
sation d’un tissu precédément organise.” ? 
1 Page 90, /oc, cit. 
