102 PROCEEDINGS OF THE ACADEMY OF [1885. 



Hibernation and Winter Habits of Spiders. — The Rev. Dr. 

 McCook remarked that the effect of a low temperature upon 

 spiders was observed in the cases of several young specimens of 

 Theridion tepedariorum. They hung on a few short lines to the 

 plastered wall of a brick out-building, the plaster being laid 

 directly on the brick, forming a very cold surface. The spiders 

 were protected from the wind and snow, but wholly exposed to 

 the frost. January 14 (1885), with thermometer ranging from 

 20° to 25° above zero (Fahrenheit), the spiders were hanging 

 motionless. When touched by the tip of a pencil the}" dropped 

 down in the usual manner of their kind, holding on by the out- 

 spun threads which reached a length of over one foot. They 

 ascended to their perch afterward, and crawled over the roof a 

 little ways. 



At a temperature of 18 - 6° the}' again were able to drop from 

 the perch. January 19, with thermometer ranging from 17 '5° to 

 20°, they seemed less active — one, when touched, dropping about 

 one inch, another six inches. Four hours thereafter they were 

 suspended in the same position. As the natural habit of the 

 creature is to ascend in a moment or two after disturbance, this 

 shows that the frost had somewhat affected the normal energy. 

 But one of them, being gently lifted on the finger, moved its legs 

 and very slowly began to ascend. Five hours thereafter it was 

 at its perch against the roof. These spiders, at this temperature, 

 with some variations (January 21), moved their position, one 

 passing along the angle of the roof, a distance of four feet. This 

 change of site was probably caused by the annoyance which the 

 experiments produced. 



February 11, the thermometer stood at zero at the City Signal 

 Service Office ; in West Philadelphia, where his observations were 

 made, the temperature was lower. On the 12th, the Signal Ser- 

 vice reported 1° above zero ; at his house it was below zero. On 

 this day he removed from its position one of the specimens, a 

 young female about two-thirds grown, and placed it in his library 

 where the temperature was summer heat. She was laid upon the 

 table in the sun. The legs were drawn up around the cephalo- 

 thorax in the usual " hunched " way when torpid or feigning 

 death. There was a slight and regular pulsation of the feet. In 

 less than ten minutes, upon being touched, she stretched forth 

 her legs and began to move slowly over the paper upon which 

 she had been placed. When touched, her motion was much 

 accelerated, and she began vigorously to perambulate her bounds, 

 anchored to and pulling out after her the usual drag-line. When 

 lifted up on the tip of a pencil she spun out a long thread, to the 

 end of which she hung in the little basket-like structure of silken 

 cords which he had elsewhere described. Indeed, her action was 

 in ever}- respect normal, and showed a remarkably sudden and 

 complete revival of activity after so long an exposure to such 

 extreme cold. 



