SCHIZONEURIN^. 83 



1875, that in Sch. americana wingless and moiitiiless 

 males are produced. Again, M. Jules Lichtenstein has 

 distinctly proved that the perfect sexes are the produce 

 of that second series of the winged generation which 

 left the galls for the purpose of dropping their young 

 in the bark fissures. These sexes soon pair, and at 

 once commence the process of oviposition of their 

 single large egg. 



Dr. H. F. Kessler, of Cassel, through many experi- 

 ments and observations, showed also that the females 

 of the Pemphigince affecting the leaves of TJlmus cam- 

 2?estris retired to the trunk in the winter to oviposit, 

 and that speedily afterwards they died. 



In 1878, M. Lucien Courchet, of Montpellier, gave 

 an excellent general resume of the Aphis group, and 

 towards the end of his memoir he fully went into the 

 description of " les Pucerons du terebinthe et du 

 lentisque." The following year he published his 

 ' Etude sur les Galles produites par les Aphidien.' 

 These observations extend over more than one hundred 

 pages. The memoirs are embellished by six well-exe- 

 cuted plates, showing the structure of the galls, and 

 furnishing various details relating to the antennjB and 

 the wing-veining of the Pempliigince inhabiting these 

 galls. 



M. Lichtenstein has patiently and successfully traced 

 some of these Aphides through their various stages of 

 development. He has employed a nomenclature to 

 distinguish the seven buddings or pseudo-births which 

 here it may be interesting to notice. 



The immediate issue from the egg he styles Pseudo- 

 gyne^ fondatrice. To all the generations except the 

 final he gives the name of Pseudogynes, but to the 

 third series, which is winged, he gives the name of 

 Pseudogynes emigrantes. The progeny of these last 

 insects is apterous, and he styles them Pseudogynes 

 hourgeomiantes. The sixth generation is also winged. 



* Pseudogyne, from iI/evloq, false, and ywii, female. The former terms, 

 Andropliore and Gynephore, have been relinquished by him. 



