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AFRICAN APHIDIDAE.— Part IL* 

 By Fred. V. Theobald, M.A. 



The following notes and descriptions of African plant-lice are based mainly on part 

 of the large collection I have received from Mr. F. C. Willcocks, made in Egypt since 

 1907 ; specimens from Mr. Gerald Bedford, collected in the Transvaal and the Cape ; 

 and a small collection of spirit specimens without any colour notes sent to the Imperial 

 Bureau of Entomology by Mr. T. J. Anderson from Nairobi, British East Africa. 

 The collection made by Mr. Willcocks in recent years contains some hundreds of 

 specimens, many in alcohol and many beautifully mounted, with field notes giving 

 the living colours of most of the species. This very valuable collection seems to be 

 almost complete for Egypt, for in a recent letter Mr. Willcocks tells me he is unable 

 to find any new species. It contains a number of new insects and some well-known 

 European and American species, including the com pest. Aphis maidis, Fitch ; the 

 green pea louse, Macrosiphum pisi, Kalt. ; Macrosiphiim sonchi, L. ; the so-called 

 yellow clover aphis of America, Callipterus trifolii, Monell, which is here shown to 

 be the Aphis {Callipterus) ononidis of Kaltenbach ; the water-plant aphid of Europe 

 and America, Siphocoryne {Aphis) nymphaeae, L.; and the European willow aphid, 

 Lachnus viminalis, Boyer. The bean-root aphid, Tychea phaseoli, Pass., was also 

 sent and the alate female is now described, as well as the first alate female of 

 Rhizobius, apparently referable to Buckton's Rhizobius graminis. A large 

 number of specimens in Mr. Willcocks' collection yet remain to be examined, 

 including species from Zizyphiis, Duranta, artichokes and sycamore figs ; also others 

 from Nairobi and some tubes of specimens sent by Dr. Aders from Zanzibar to the 

 Imperial Bureau. 



It may be once more pointed out that many specimens sent in spirit with no 

 colour notes are almost impossible to identify with any degree of certainty. 

 Colour is one of the main things in identifying these insects from old 

 descriptions. Until definite structural characters are given we may have to 

 rely on these. At present comparatively httle is known of plant-lice in 

 Europe and America, the only parts of the world in which they have been at 

 all studied or even collected. With increasing information it appears that many 

 species have a world-wide distribution, as for instance Callipterus ononidis, Kalt., 

 which seems to be common to America, India, Europe and Egypt. Owing 

 to the somewhat crude descriptions of many of the older species and the lack 

 of any real structural characters, it is extremely difficult to say if any particular 

 aphid coming from any part of the world is the same or distinct from one coming 

 from elsewhere. Colour alone is of no value, it may cause considerable confusion in 

 identifying these insects, so far as the original descriptions go. One instance ^vill 

 explain this. A wheat aphid sent by Mr. Willcocks from Eg}^pt is undoubtedly 

 Toxoptera graminum, but the colour notes he sends of this insect do not agree with 

 those of this corn pest of Europe and America. On the other hand the aphid described 



* For Part I. see Bull. Ent. Res., iv., p. 313. 

 (C177) ^2 



