Chapter VI — 101 — Parallelisms in Distribution 



that there grew there either Pislacia mutica or some closely related 

 species of this genus. This louse, therefore, must have Hved through 

 the Ice Age in Greenland, which gives grounds for presuming that not 

 all representatives of the Angiospermae were destroyed by the great 

 cHmatic changes of that period. The secondary hosts on which this 

 louse passed its life cycles must also have been preserved in sheltered 

 places not covered by the ice. That this louse penetrated into Green- 

 land from Europe, by way of Iceland, is not possible, since it is not 

 found in Iceland. In that country there is found another louse. 

 Pemphigus hursarius, whose primary host is the poplar, Popidus nigra. 

 It spreads considerably more rapidly than the preceding species; 

 nevertheless, it is not found in Greenland (Mordvilko, 1935). These 

 facts fully coincide with recent data on the origin of the flora of higher 

 plants in Greenland, pointing to the likelihood that some of its species 

 lived through the Ice Age. 



As a final example, we may take the plant-louse, Forda hirsuta 

 (primary host — Pislacia vera). The fact that the microcyclic form of 

 this louse is not found in Europe shows that Pistacia vera never oc- 

 curred on the territory of Europe. 



The data we have here presented make evident the need for more 

 detailed studies of the interrelations between plant and animal organ- 

 isms from the point of view of their geographical distribution. 



References: 



CoCKERELL, T. D., 1932: Discontinuous distribution in plants (Nature, Vol. 130, No. 

 3291)- 



Geptner, V. G., 1936: Principles of Zoogeography (In Russian; Moscow-Leningrad). 



Lashchevskaya, V. I., 1927: A contribution to the problem of the origin of the flora 

 of the Kursk-Orel plateau: Puccinia drabae Rud. and Schivereckia podolica (Boss.) Andrz. 

 (In Russian; BuU. Sci. Res. Inst., Voronezh Univ.). 



Mordvilko, A., 1925: Analozyldische Uredinales und ihr Ursprung (Biol. Centralbl., 

 Vol. 45, No. 4, pp. 217-231). 



Mordvilko, A., 1925/26: Die Evolution der Zyklen und die Heterozie bei den Rost- 

 piLzen (Centralbl. f. Bakteriol., Parasitenkunde u. Infektionskrankheiten, Vol. 66, pp. 

 50S-S3I)- 



Mordvilko, A., 1928: The evolution of cycles and the origin of heteroecy (migrations) 

 in plant-lice (Annals and Magazine of Nat. History, Ser. 10, Vol. 2, pp. 570-582). 



Mordvilko, A., 1929: Analocyclic elm aphids, Eriosomea, and the distribution of ehns 

 during the tertiary and glacial periods (Comptes Rendus Acad. Sci. U.R.S.S.). 



Mordvilko, A., 1929: Die analozyklischen Pistazien-Blattlause und die Verbreitung 

 der Pistazien in der Tertiarzeit (Comptes Rendus Acad. Sci. U.R.S.S.). 



Mordvilko, A., 1930: Pemphigus bursarius Tullgren (pyriformis Licht.) and its analo- 

 cycUc forms (Coniptes Rendus Acad. Sci. U.R.S.S., pp. 50-54); Aphids of the Subtribe 

 Bormaphidina {Ibid., pp. 168-172). 



Mordvilko, A., 1930: On the origin of heteroecy in plant-lice (Comptes Rendus Acad. 

 Sci. U.R.S.S., pp. 256-260). 



Mordvilko, A., 1935: Die Blattlause mit unvoUstandigem Generationszyklus und ihre 

 Entstehung (Ergebn. u. Fortschr. d. Zoologie, Vol. 8). 



Reinig, W. F., 1937: Die Holarktis. Ein Beitrag zur diluvialen und alluvialen Ge- 

 schichte der zirkumpolaren Faunen u. Florengebiete (Jena). 



Scott, Hugh, 1933: General conclusions regarding the insect fauna of the Seychelles 

 and adjacent islands (Trans. Linn. Soc, Ser. 2, Zoology, Vol. 19, Part 3). 



Steyeruark, G. a., 1932: A revision of the genus Menodora (Ann. Mo. Bot. Card., 

 Vol. 19, No. i). 



Transhel, V. A., 1936: Rust fungi as indicators of the relationship of their hosts in 

 connection with the phylogenetic development of rust fungi (In Russian). 



Transhel, V. A., 1940: The Rust Fungi of the U.S.S.R. (In Russian; Moscow-Lenin- 

 grad). 



