90 Dr. Burnett on the Development of Viviparous Aphides. 



again and again after the first impregnation, have a receptaculum 

 seminis connecting with the oviduct, in which the semen is 

 deposited during coition, and where it may be preserved without 

 losing its vitahzing power for several months*. Thus, by this 

 provision, the males, having copulated with the females in the 

 autumn, may immediately die, while these last, hibernating, pro- 

 duce in the spring fertile ova ; and in the instance of the Bombus 

 americana, such a coition suffices for all the three broods which 

 are produced the ensuing summer. 



Another explanation of these curious phsenomena, and which 

 has attracted some attention, as well from its singularity as from 

 the eminence of its propounder, is that of Owen, advanced in his 

 Hunterian Lectures in 1843t. 



He affirms that the larval Aphides are productive in virtue of 

 the successive continuation from brood to brood of a portion of 

 the primitively fertilized germ, and which material product or 

 leaven is not exhausted until nine to eleven generations. I will 

 quote his own language : " In the Aphides the corresponding vi- 

 telline cells retain their share of the fecundating principle (which 

 was diffused through the parent (t^^ by the alternating, fissipa- 

 rous,liquefactive, and assimilative processes) in so potent a degree, 

 that a certain growth and nutritive vigour in the insect suffice to 

 set on foot in the ovarian, nucleated cells, a repetition of the fissi- 

 parous and assimilative process, by which they transform them- 

 selves in their turn into productive insects ; and the fecundating 

 force is not exhausted by such successive subdivision until a 7th, 

 9th, or 11th generation.^^ This same doctrine, the successive 

 inheritance of a portion of the primary germ-mass from brood to 

 brood, and by means of which the fertile germs are continued, 

 — this doctrine, I say, is repeated in full in this author^s work on 

 Parthenogenesis, and I will here quote one sentence, not only in 

 illustration of this, but to show how different his own observa- 

 tions on the development of these animals are from mine, just 

 described. He says, " One sees such portion of the germ-mass 



* For many details on this subject of the receptaculum seminis, see 

 Siebold, Miiller's Arch. 1837, p. 392 ; also in Wiegmann's Arch. 1839, i. 

 p. 107 [Vespa], and in Germar's Zeitsch. ii. (1840) p. A42{Culex). See also 

 Stein, Vergleich. Anat. &c. 1847, p. 96, 112. I cannot but believe that the 

 anomalous reproductive conditions of the Cynipida? will, at last, have a solu- 

 tion equally satisfactory. See Hartig, Germar's Zeitsch. ii. p. 178, and iv. 

 p. 395. See also Siebold and Stannius's Comparative Anatomy, transl. i. 

 sect. 348, notes 1 & 4. 



t Lectures on the Comparative Anatomy and Physiology of the Inverte- 

 brate Animals, &c. London, 1843, p. 233. This explanation is lately in- 

 sisted upon (strange to relate) in his recent work " On Parthenogenesis, or 

 the successive production of procreating individuals from a single ovum." 

 London, 1849. 



