^348. 



THE INSECTA. 



447 



are much less numerous than the males. In the colonies of Bees, Ter- 

 mites, and Ants, there are, beside the males and females, a multitude of 

 neuter individuals known as the Workers or Soldiers. 



The sexual parts of insects are developed chiefly during the pupa-state ; 

 but their rudiments exist already in the youngest larvae, with which the 

 sexes may then be distinguished.'-' 



The female genital organs persist in a rudimentary germ-like condition 

 with many larvae of Bees, probably owing to the influence of nourishment, 

 for by increasing that of the workers these last may be raised to the rank 

 of females or Queens.'"* 



The Aphididae are very remarkable in that they produce, for several 

 successive generations, only females which, in their, turn reproduce, but 

 viviparously and without the direct influence of the males.**' 



The genital organs of the Insecta are composed in general, of two symmet- 

 rical Ovaries, or Testicles, situated in the abdominal cavity, and of two 

 oviducts, or Deferent canals (Tubae, or Vasa defer entla) which unite in a 

 common excretory duct (Vagina^ or Ductus ejaculatorius) opening back of 



2 Herold (Entwickelungsgesch. d. Sohmetterl.) 

 has made very interesting researches on this pre- 

 mature development of the genital organs with 

 Pontia brassicae, and which accord with the ob- 

 servations of Suc/coiv (Anat. u. physiol. Untersuch. 

 p. 31, Taf. III. V.) on those of Gastropacha pint. 

 See, also, Herold, Uisquisit. de Animal.Vertebr. car- 

 ent. in ovo format. Tab. I. fig. 9, or Ann. d. Sc. Nat. 

 XII. 1839, p. 186, PI. VII. fig. 8. To be con- 

 vinced that in the other orders of Insecta the geni- 

 tal organs are also developed at a very early 

 period, it is only necessary to cast a glance over 

 the figure which Suckow {Heusin^er^s Zeitsch. 

 II. Taf. X. fig. 9) has given of Aphrophora spu- 

 maria, and L. Dufour (Ann. d. Sc. Nat. XIII. 

 1840, PI. III. fig. 5) ot Pyrnchroacoccinea. 



3 For the origin of the neuters with the Hymen- 

 optera, see Treviranu.i, Zeitsch. f. Physiol. III. 

 p. 220. In all the bee-workers there are found 



* [ § 348, note 4.] The peculiar economical re- 

 lations of certain Hymenoptera (Ci//h';).s) referred 

 to above have received some explanation by the 

 researches of F/"aMfnrfor/(IIardinger Berichte iib. 

 d. Mittheil. v. Freunden d. Naturwiss. in Wien. IV. 

 p. 247, or fViegmann's Arch. 1849, Th. II. p. 

 118), upon Gastropacha lanestris. lie gathered 

 two nests of the larvae at the end of June, 1836 ; 

 by the middle of August the caterpillars had spun 

 up, and on Sept. 18, the first imago appeared, and 

 the second on Dec. 14 ; both of these were males ; 

 in the spring of 1837, some twenty individuals of 

 both sexes appeared; others, likewise, in the autumn 

 of 1837 i others still in the following year, and the 

 last of them on the 4th of March, 1842. The pupa- 

 state of the last of the brood was therefore five and 

 a half years, while that of the first was only as 

 many weeks. 



In regard to the alleged anomalous reproductive 

 relations of Psyche, they have received the special 

 attention of Siebold, who has quite cleared up the 

 subject (Ueber der Fortpflanzung von Psyche : Ein 

 Beitrag z. Naturgeschichte der Schmetterlinge, in 

 Siehold and K6lUker''s Zeitsch. I. 1843, p. 93 ; 

 also in his Bericht iib. die entoraol. Arbeiteu d. 

 echles. Gesellsch. im J. 1850, or its transl. in tb» 



vestiges of the ovaries and of the seminal receptacle. 

 See Ratzebur^, Nov. Act. Nat. Cur. XV. part II. 

 p. 613, Tab. XLVII. and my observations in Ger- 

 ?nar\s Zeitsch. IV. p. 375. 



i This mode of generation of the Ai)hididae (see 

 § 350) quickly reminds one of that which Steen- 

 strup has called Alternate Generation. Certain 

 species of Cynips belong probably to the same cat- 

 egory, for their males have yet been undiscovered. 

 Hartig {Germar''s Zeitsch. IV. p. 398) has been 

 unable to find any individuals of this sex among 

 thousands of Cynips folii and divisa. Similar 

 observations have been made by L. Dufour (Re- 

 cherch. sur les Orthopt. &c. p. 527). It is to me 

 probable, also, that the capacity wliich many ento- 

 mologists attribute to Psyche of laying eggs with- 

 out a previous copulation is an example of alternate 

 generation.* 



Transact, of the Entom. Soc. London, 1. 1851, p. 234. 

 In the first of these researches made upon the 

 genera P«i/cAe and Fumea, there was no evidence 

 that, with the individuals of these genera, reproduc- 

 tion occurs in an anomalous manner, that is, with- 

 out the aid of the male ; on the other hand, the 

 facts of the well-developed character of the inter- 

 nal genital organs of the females, and of the capacity 

 of the male to impregnate the female while she is 

 concealed deeply in her case — these precluded the 

 hypothesis of Lucina sine concubitu. But sub- 

 sequent researches made upon Talaeporia have 

 shown him that, with the individuals of this genus, 

 non-se.xual reproduction does occur, presenting sim- 

 ilar phenomena and conditions as the generation of 

 the viviparous Aphides. It is proper to remark, how- 

 ever, that the carefully-made researches and exper- 

 iments of Speyer upon the genital organs and mode 

 of reproduction of Talaeporia ijcAeneZto, several 

 years before, had shown that two successive genera- 

 tions here occur without the presence of males ; see 

 his paper in the Entom. Zeit. 1847, p. 18. For the 

 phenomena and their interpretation of the develop- 

 ment of the viviparous Aijhididae, see my note at 

 § 355, end. — Ed. 



