1884.] • 179 



I tried, on receiving the notice of my learned friend of Budapest, 

 to make the contrary proofs, and to bring the winged spring-forms 

 of all elm-feeding plant-lice on to maize-roots. Contrary to my ex- 

 pectation, the only Pempliiqus known on elm (P. pallidus, Haliday, 

 suh Eriosoma) died without touching the roots ; while, on the con- 

 trary, another elm-louse, viz., Tetraneura uhni, immediately fixed itself, 

 sucking at the roots, and improving in size. 



Greatly puzzled by the fact, I wrote to my friend in Hungary : — 

 " Please send me what you call Pevtphigtis zece-mmdis." He did so at 

 once, and I immediately recognised by the neuration of the under- 

 wings, and the relative length of the antennal joints, that the insect 

 was not a Pemphigus, but the very same Tetraneura uhni, Auct. 



I consulted the authorities on Aphidology, M. Passerini of Parma, 

 Kessler of Cassel, Low of Vienna, and Ferrari of Genoa, asking for 

 specimens of their Pemphigus zece-mdidis or Boyeri, and sending 

 Horvath's examples for comparison: the result of my enquiries was 

 that both insects are the very same thing, and that Hartig's character 

 of the neuration of the under-wings in the genus Tetraneura cannot 

 be absolutely relied on, as there is sometimes a second very feeble 

 nervure in some examples, but that the character easy to seize, viz., 

 the 5th antennal joint being equal to the 3rd, sufficiently distinguishes 

 Tetraneura uJmi from all other elm-lice. 



Meanwhile, as maize is not commonly cultivated in our district, 

 whereas Tetr. ulmi is exceedingly abundant, I searched at the roots 

 of various grasses, and found that those of Cynodon dactylon were also 

 attacked by the same underground lice. In October, they changed to 

 nymphs, and to winged forms. I had a certain number in glass tubes, 

 where they soon deposited their sexed proles without rostrum, and I 

 witnessed the pairing, after which the female dies, conserving her 

 unique egg in the dried skin. I had already discovered the female in 

 1878 {vide Ent. Mo. Mag., vol. xiv, p. 224). But, in addition to this, 

 I made experiments at large at my cottage at La Lironde, and, as the 

 trunks of my young elms seemed to me too smooth to offer a good 

 shelter to my pupiferous pseudogynce, I tied round them a band of 

 paper, and placed on it some winged-lice collected at the grass-roots. 

 They did not fly away, but, on the contrary, finding probably the place 

 to their taste, they passed between the paper and bark, and began to 

 lay their sexed young ones. 



But what is still more astonishing, they served as an attraction 

 for other lice from the surrounding fields, where Cynodon dactylon 

 grew, and already, on the following day, my paper band was crowded 



