Structure and Economy of Spiders. 483 



effected, it will suffice to detail the proceedings of a single spe- 

 cies ; and as Epeira calophylla is of frequent occurrence about 

 retired buildings situated in the country, and, consequently, 

 may be procured without difficulty, I shall select it for the pur- 

 pose. Preparatory to casting its integuments, this spider spins 

 several 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 

 corneous covering of the thorax gives way, — not in the medial 

 line of the dorsal region, as Dr. Leach's statement would seem 

 to imply, but laterally, disuniting immediately above the inser- 

 tion of the mandibles and legs, so that the head and thorax are 

 the first parts liberated. The line of separation pursues the 

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

 engaged ; the extrication of the legs being the last and greatest 

 difficulty which the spider has to overcome. As the suspensory 

 filament connected with the spinners of the exuviae is consider- 

 ably shorter than the legs, and does not undergo any sensible 

 alteration in length, the abdomen, during the process of moult- 

 ing, becomes gradually deflected from its original horizontal 

 direction, till it assumes a vertical position nearly at right 

 angles with the thorax. 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. The spines with which the legs are 

 provided no doubt contribute to facilitate the operation greatly; 

 for as they are directed down the limbs, and are moveable at 

 the will of the animal, when it has partially withdrawn the legs 

 from their sheaths by contracting them, it can prevent them 

 from re-entering by slightly erecting the spines and thus bring- 

 ing their extremities in contact with the inner surface of the 

 integuments. When the spider has completely disengaged itself 



from 



