322 



FRED. V. THEOBALD — 



Pi/rus communis, Cornus mas and all varieties of Citrus ; Datura stramonium, 

 Cosmia sp., Begonia, Hydrangea, Hibiscus, etc. 



The African specimens sent me by Mr. F. C. Willcocks from Lower Eygpt 

 and those from British East Africa and the Transvaal agree exactly with the 

 American specimens I have and with those found on melons under glass in Britain. 

 The species is subject to great variation in colour, ranging from pale greenish 

 yellow to almost black, but can at once be told by the antenna! sensoria of the 

 al ate female and by the cauda. 



Pergande says the sensoria on the third antennal segment in the alate female 

 vary from 5 to 7. I have several times counted as many as 8, never more, the 

 usual number being 5. It is probably a world-wide species. It is thought 

 by Lounsbury to be indigenous to Africa, where it was first noticed in 1907 

 attacking melons. Whole fields of watermelons and cucumbers were killed in the 

 Cape Peninsula, and calabashes were also attacked. The aphis that caused such 



B 



C 



Fig. 5. — Aphis gossypii, Glow ; (A) head and antenna of alate 9 ; (B) cornicle, and (C) cauda 

 of alate 9 '■> (D) head and antenna, (E) cauda, and (F) cornicle of apterous 9 • 



loss to melon-growers in 1896 at Constantia, the Cape Flats and Paarl was 

 undoubtedly this species. Lounsbury speaks and writes of it as the Melon 

 Aphis.* In America it appears to be common on oranges, but in Africa it is 

 rare upon Citrus fruits. The aphis from melons in the Sudan that I thought 

 was probably Koch's A. malvae is A. gossypii, and it also occurs commonly on 



Cosmia sp. in the Transvaal. 



Gillette (Journ. Econ. Ent. i, pp. 176-181) states that so far no eggs of this 

 species have been found. Reproduction appears to be entirely asexual, as is the 

 case with Aphis abietina, Walk., in Britain. 



In Africa A. gossypii is preyed upon by a Ladybird Beetle (Chilomen.es 

 lunata) and by several species of Syrphid larvae. In India it is attacked by a 



Trionyx sp. (Lefroy). 



Leaflet 28, Dept. Agric. Cape Col. (1906). 



