STBUCTURE, FUNCTIONS AND CECONOMY OF ARANEIDEA. 69 



to a female of its own species, ■which had been in solitary confinement from 

 the 25th of January 1840, and had cast its skin three times during its captivity. 

 This female received the embraces of the male as soon as he was admitted 

 into the phial to her, and laid a set of eggs on the 27th of the same month, 

 all of which were productive, the young beginning to be disengaged from them 

 on the 27th of the ensuing month. 



In stating a further repetition of this experiment with spiders of the same 

 species, it is only necessary to premise that the female had cast her skin three 

 times in captivity, and that the male had but the right palpus, the other having 

 been removed by amputation. They were placed together on the 16th of May 

 184-2, paired the same day, and were separated as soon as their union was ac- 

 complished. On the 19th of June the female deposited a set of eggs in a 

 cocoon, which began to be hatched on the 24th of the following July, and all 

 produced young. Without further sexual intercourse, in 1843 she enveloped 

 a set of eggs in a cocoon on the 7th of April, the 5th of May, the 1st of June, 

 the 18th of June, and the 3rd of July, respectively, from all which young were 

 disengaged. 



Promptness in accommodating itself to the restraint of confinement, together 

 with the certainty of being able to procure specimens whenever they might be 

 required, led to the selection of Tegenaria civilis as a suitable subject for the 

 foregoing experiments, from which, conjointly with the preceding observations, 

 the following inferences may be deduced : — 



1st. That female spiders are incapable of producing prolific eggs without 

 sexual intercourse. 



2nd. That females which have not been impregnated occasionally produce ' 

 sterile eggs. 



3rd. That the female of Tegenaria civilis, when impregnated, is capable of 

 producing several sets of prolific eggs in succession without renewing its in- 

 tercourse with the male*, two years or more occasionally elapsing before all 

 are deposited, and a period often months nearly intervening sometimes between 

 the deposition of two consecutive sets. 



4th. That spiders of various species copulate without the abdomen of the 

 male being brought into contact with that of the female. 



5th. That male spiders, in which the part stated by Treviranus to be the 

 seat of the sexual organs is entirely covered with strong, well-gummed writing 

 paper closely applied, nevertheless possess the power of exercising the function 

 of generation unimpaired. 



6th. Lastly, that males so circumstanced invariably consummate the act by 

 applying the palpal organs to the vulva of females, plainly demonstrating 

 thereby the interesting truth, that those organs, however anomalous their 

 situation may be, are the only efficient instruments employed by male spiders 

 in the propagation of their species. 



Before they arrive at maturity spiders change their skin several times : the 

 manner in which these moults are effected may be illustrated by describing 

 the proceedings of an individual of the species Eptira calophylla. Pre- 

 paratory to casting its integument, this spider spins some strong lines in the 

 vicinity of its snare, from which it suspends itself by the feet and a filament 

 proceeding from the spinners. After remaining for a short time in this 

 situation, the coriaceous covering of the cephalothorax gives way laterally, 

 disuniting at the insertion of the legs and mandibles ; the line of separation 

 pursues the same direction till it extends to the abdomen, which is next dis- 



* Tegenaria domestica {Araneadomestica, Linn.), Jgelena labyrinthica, and Epeira cucurbi- 

 lina are endowed with similar powers of production. Vide the Report of the Third Meeting of 

 the British Association, p. 445. 



