AND MORPHOLOGY OF APHIS. 197 



" I am indebted to my friend Mr. Haliday for the following translation of an extract 

 from Erichson's Berieht, &c., 1844, Ent. Zeitung, pp. 9, 81, 133, 410. Ratzeburg observed 

 a species of Aphis on the Birch, which continued to produce a living progeny from 

 August into winter without either male or female appearing. Bouche and Kaltenbach, 

 in explanation, remark that the males in this family are not always winged. However, 

 in the May following, Ratzebm'g, continuing his observations, found the winged females, 

 and afterwards (in October) winged males also, which paired with them. The species was 

 then identified as^. oblonga, Von Heyden. For the male to pair with a winged female 

 (continues Mr. Walker) is a very unusual case among Aphides*." In fact, I have hitherto 

 found, in Mr. Walker's long list of 101 species, no case of an oviparous winged female 

 observed by himself. Mr. Walker states as a known fact, that Ap)his Rosa; habitvxally 

 lives through our mild winters. 



In his work on ' Parthenogenesis' (1849), Prof. Owen modifies his previous statement 

 so far as to say, in a note (p. 59), that the perfecting of the female generative organs in 

 Aphis " is not attended by the acquisition of wings ; or if they be developed in the ovipa- 

 rous female, they soon fall. I have, however, retained them in the diagram for a better 

 illustration of the analogy. Many of the virgin viviparous Aphides acquire wings, but 

 never perfect the generative organs." 



The diagram referred to exliibits two figures, {h) and (i), which, for anything that 

 appears in the text, might be taken to be the author's representation of male and female 

 Ajjhides. On comparing them with the illustrations of Morren's memoir, however, it is 

 at once obvious that they are copies of his figures 1 and 2, of which fig. 2 does really 

 represent a male ; while fig. 1, on the other hand, is not an oviparous, but a viviparous 

 female. In the explanation of liis figures, Morren indeed merely says of fig. 1, " Femelle 

 vue en dessous ;" but it requires no great amount of attention to his text to observe his 

 distinct statement (ali-eady quoted), that the winged female is vivijiarous, and not ovipa- 

 rous. I am obliged to be thus particular in explaining these unusual cu'cimistances, as 

 otherwise the existence of a typical figure of a winged oviparous female Aphis, in the 

 work of an accredited author, might be brought forward as conclusive evidence of the 

 ordinary occurrence of such females t- 



* On turning to Ratzeburg's notice in the ' Entomologische Zeitung,' 1844, p. 410 (Fortgesetzte Beobachtungen 

 iiber die Copula der Blattliiuse), which is the last word of the correspondence between Kaltenbach, Bouche and him- 

 self on this subject, I find his precise words to be these : — " Wie gross war daher mein Erstaunen, als ich bei meiner 

 ersten, nach der Riickkehr angestellten Excursion, am 22 October gleich auf den ersten Blick unter der Menge von 

 unyeJlUgelten Inrlicidtien, welche die des vorigen Jalires bei weitem iibertraf, auch geflUgelte Pupjien uiid geJtiigeJte 

 Miinnchen bemerkte, und wie gross war meine Freude, auch gleich darauf mehrere der letztern in der Begattung zu 

 finden, also in eineni Acte, den ich bei Blattlausen selbst noch nicht hiitte beobachten konnen." Subsequently, Ratze- 

 burg states that he was able to observe the copulatory process early and late, at any time between the 22nd October 

 and the 16th November. 



It will be observed that there is not a word here about such winged females as Ratzeburg, in a preceding passage, 

 states he saw in May of the same year. The winged pupae are apparently, from the context, the pupse of the males, 

 and the forms with which the winged males copulated were the wingless females. So that here, as in all other sup- 

 posed cases of winged, oviparous true .\phides I have looked into, the evidence, when closely examined, breaks down. 



t Professor Owen, in the last edition of his 'Lectures on the Invertebrata,' p. 410, quotes Le'on Dufour as having 

 witnessed the coitus of the male Aphis " with the winged female." The reference is to " Dufour, Leon, in Aimales 



2d 2 



