DKATH AND ITS DISGUISES. 435 



health and activity, within the waters of a frozen pond, in midwinter, 

 and so far from the bank in which their burrows are commonly found. 

 It has been believed heretofore, and doubtless it is generally true, that 

 Lycosids winter in deep burrows in the ground, sealed up tightly to main- 

 tain a higher temperature. But the above observation opens a new and 

 strange cliapter in the winter behavior of these araneads, as well as in tlie 

 amphibious nature of their habits.' 



IV. 



The effect of low temperature upon spiders was observed in several 

 young specimens of Theridium tepidariorum. They hung on a few short 

 lines to the plastered wall of a brick building on my premises, 

 tion ' *'"^ plaster being laid directly on the brick, forming a cold sur- 

 face. The spiders were protected from wind and snow, but 

 wholly exposed to the frost. On January 14th (1885), with thermometer 

 ranging from 20° to 25° above zero (Fahrenheit) the spiders were hang- 

 ing motionless. When touched by the tip of a pencil they dropped down 

 in the usual manner of their kind, holding on by the outspun threads, 

 which reached a length of over one foot. They ascended to their perch 

 afterward, and crawled over the roof for a short distance. 



At a temperature of 18.6° they again were able to drop from the perch. 

 January 19th, with the thermometer ranging from 17.5° to 20°, they seemed 

 less active ; one individual, when touched, dropped about one inch, another 

 six inches. Four hours thereafter they were suspended in the same posi- 

 tion and place. As the natural habit of the creature is to ascend in a 

 moment or two after disturbance, this shows that the frost had affected 

 the normal energy. One of the specimens, however, on being gently lifted 

 upon my 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 21st), moved their position, 

 one passing along the angle of the roof u distance of four feet. This 

 change of site was probably caused by the annoyance which my experi- 

 ments produced. 



February 11th the thermometer stood at zero; in West Philadelphia, 

 where my observations were made, the temperature was lower. On the 

 12th the Signal Service reported 1° above zero, at my house it 

 Sudden ^^^ below zero. On this day I removed from its position one 

 tation °^ ^^^'^ specimens, a young female about two-thirds grown, and 

 placed it in my library, where the temperature was summer 

 heat. She was put upon a table in the sunshine, at which moment her 

 legs were drawn up around tlie cephalothorax in the usual hunched way 

 when torpid or feigning death. There was a slight and regular pulsation 



Proceed. Acad. Nut. Sci., I'liiliidclphia, 1H84, page 140. 



