562 



(Aphis pninorum, Dobr.), migrates from plums and apricots to various 

 other plants such as Nymphaea and Alisma ; it is believed that 

 R. [A.) itififscata, Koch, occurring on blackthorn is identical with this 

 species. 



A. ])omi, De G. {mali, F.), attacks apples ; A. grossulariue, Kalt., 

 on the young shoots of both red and black currant and gooseberries ; 

 A. hburni, Kalt., occurs on Robinia pseudacacia, though it is unknown 

 whether it lives on this tree the whole year or only during the summer 

 months ; A. rumicis, L., occurs on maize, poppy, beet, Chenopodinm 

 album, Atriplex, Cirsiu))), and Lappa tomentosa ; A. brassicae, L., is 

 said by some authors to occur on beet and spinach, but the correctness 

 of this statement is disputed, A. nmiicis being evidently in such cases 

 mistaken for it. Davis has lately described a new species, A. psei'do- 

 brassime [see this Revieiv, Ser. A, ii, p. 604], but the author believes 

 that this is A. erysimi, Kalt., which he has found near Kiev on Brassica 

 rapa, Sinapis arvensis, Raphanus raphanistrum, Erysimum cheiran- 

 Ihoides, and Capsella biirsa-pastoris. A. pyri, Boy., occurs on apples ; 

 the author agrees with Baker [see this Review, Ser. A, v, p. 49] in 

 treating this species as distinct from A. crataegi, Kalt., which is unable 

 to live on apple ; there also occurs on apple trees a sj^ecies resembling 

 in many respects both A. pyri and A. crataegi and more especially 

 A. radicola, Mordv., on roots of sorrel. A. cardui, L. {pruni, Koch), 

 occurs on Lappa minor ; the author has already established the 

 identity of these two forms [see this Review, Ser. A, ii. p. 81] and 

 further experiments in 1915 have finally confirmed the fact that 

 A. cardui migrates in summer to Senecio vulgaris and CapseUa bursa- 

 jmstoris, and that A. jacobaeae, Schr., and A. capsellae. Koch, hibernat- 

 ing usually on plums, are synonyms of it. A. cardui can also winter 

 on some intermediate plants such as Senecio and Carduus, either as 

 j^arthenogenetic females or in the egg. Under the name of A. insititiae, 

 Koch has described the stem-mother and winged forms of the second 

 generation of A. cardui. Borner has recorded the migration of 

 A. cardui to various grasses, but the species he was studpng was 

 A. myosotidis, Koch, which has been observed by the author to migrate 

 from plum to Myosoiis intermedia, M. palustris, Senecio rvJgaris, 

 Solidago virga-aurea and Erigeron canadense. 



Plotnikov (V.). riorOAa M BpefiMienM pacieHiil. [The Weather and 

 Pests of Plants.] — Pubhshed by the Turkestan Entomological 

 Station, Tashkent, 1917, 7 pp. 



The w^eather of the spring and summer of 1917, which was 

 characterised by a recurrence of frosts in April and by an intense 

 drought, provides a convincing illustration of the connection existing 

 between meteorological conditions and the nature and numbers of 

 insect pests. The drought especially affected the breeding of Docio- 

 staurus {Stauronoius) maroccanus, the eggs of which require a certain 

 amount of warmth and moisture for their development. Many 

 individuals perished in the eggs, while still in the last embryonic stage ; 

 others, although they succeeded in hatching, were unable to leave the 

 egg-clusters ; and those locusts that appeared in spite of all these 

 unfavourable conditions perished from the absence of food on the 

 dried-up steppes. The number that reached the winged stage was 



