70 REPORT 1844. 



engaged, the extrication of the legs being the last and greatest difficulty the 

 spider has to everconie. As the suspensory filament connected with the 

 spinners of the exuviae is considerably shorter than the legs and does not un- 

 dergo any sensible alteration in length, the abdomen, during the process of 

 moulting, becomes gradually deflected from its original horizontal direction 

 till it assumes a vertical position nearly at right angles with the cephalothorax. 

 By this change of posture, attended with numerous contortions of the body, 

 and alternate contractions and extensions of the limbs, the spider is ultimately 

 enabled to accomplish its purpose. When it has completely disengaged itself 

 from the slough, it remains, for a short period, in a slate of great exhaustion, 

 suspended solely by a thread from the spinners, connected with the interior 

 of the abdominal portion of the cast skin, which is much corrugated. After 

 reposing a little, the spider further attaches itself to the suspensory lines by 

 the claws of the feet, and when its strength is sufficiently restored, and its 

 limbs have required the requisite degree of firmness, it ascends its filaments 

 and seeks its retreat*. 



Recent observations establish the fact that the number of times spiders 

 change their integument before they become adult is not uniformly the same 

 as regards every species. A young female JEpeira calophylla, disengaged 

 from the egg on the 30th of March 1843, moulted on the 8th of the ensuing 

 month in the cocoon, which it quitted on the 1st of May ; moulting again, in 

 the same year, on the 4th of June, the 22nd of June, the 12th of July, and 

 the 4th of August, respectively, when it arrived at maturity, having cast its 

 skin five times. 



An egg of Epeira diadema, hatched on the 14th of April 1843, produced 

 a female spider, which moulted in the cocoon on the 24th of the same month ; 

 on the 3rd of May it quitted the cocoon, and moulted again on the 21st of 

 June, the 10th of July, the 3rd of August, and the 23rd of August, in the 

 same year. On the 28th of February 1844 it died in a state of immaturity 

 after having completed its fifth moult. 



On the 27th of June 1842 an egg of Tegenaria civilis produced a female 

 spider, which underwent its first moult in the cocoon on the 10th of the ensuing 

 July ; quitting the cocoon on the 21st of the same month, it moulted again 

 on the 17th of August, the 4th of September, and the 26th of September, 

 in the same year; and on the 26th of January, the 9th of April, the 24th 

 of May, the 21st of June, and the 5th of August in 1843, when it arrived 

 at maturity, having changed its integument nine times. 



A male Tegenaria civilis, extricated from the egg on the 27th of June 

 1842, also moulted nine times, casting its skin in the cocoon on the 10th of 

 the following July ; on the 21st of the same month it abandoned the cocoon, 

 moulting again on the 13th of August, the 10th of September, and the 13th 

 of October, in the same year ; and on the 1st of February, the 25th of April, 

 the 17th of June, the 13th of July, and the 17th of October in 1843, when 

 its development was complete. 



Modifications of food and temperature exercise a decided influence upon 

 the moulting of spiders. A young female Tegenaria civilis disengaged from 

 the egg on the 24th of July 1842, on the 2nd of the following August 

 moulted in the cocoon, which it quitted on the 12th of the same month, casting 

 its skin again on the 29th of August, and the 10th of October, in the same 

 year ; being scantily supplied with nutriment, it increased very little in size, 

 and died on the 4th of July 1843, having changed its integument three times 

 only. Another female of the same species, which was extricated from the 

 egg on the same day as the foregoing individual, and was well-fed, on the 13th 

 * Transactions of the Linnaean Society, vol xvi. p. 482-484. 



