STRENGTH OF WEBS AND POWER OP SPIDERS. 245 



Governor Knott also sent me the foregoing (Fig. 223) memory sketch 

 of the position of the mouse and the characteristics of the snare and the 

 entangling lines. 1 



The testimony and observations thus obtained are of such a char- 

 acter as to establish beyond any doubt these facts : First, that a young 

 living mouse was in some manner securely entangled in the 



The Con- gnare o f a gp^er Second, that the spider, by means of silken 

 elusion. , . , T ,, ,, , 



lines two or three feet long, hoisted the mouse through a 



perpendicular distance of four or four and a half inches. Third, that 

 the mouse was entangled in the spider's web by the tail alone, and 

 although it lived for at least ten hours, during which it struggled 

 vigorously to -escape, was unable to free itself, and finally died. Fourth, 

 that the hoisting process continued during Monday from about 11 A. M. 

 until the night of Tuesday following, a period of thirty-four hours, 

 when the web was accidentally broken, and then brushed away. Fifth, 

 that the specific identification of the spider heroine of this exploit was 

 at first somewhat in doubt ; and the credit seemed to lie between a Tube- 

 weaver, the Medicinal spider (Tegenaria medicinalis), and the common 

 Line weaver (Theridium tepidariorum). The accounts of the captor's be- 

 havior during the hoisting of her victim, especially swathing her victim, 

 and the opinions of the various eye witnesses to whom were sent descrip- 

 tions and drawings of both species and their characteristic webs, point to 

 the Lineweaver. I was much perplexed by the conflicting testimony in- 

 evitable in the reports of the several untrained observers. But persistent 

 correspondence and the kindness of Mr. Hopper and others finally pro- 

 cured me specimens which were declared to be undoubtedly identical 

 with the mouse catcher. These specimens are Theridium tepidariorum ; 

 to this spider, therefore, must be given the credit of the achievement. 2 

 Sixth, a comparison of the weight of a young mouse 3 with the actual 

 power of resistance in webs of both Theridium tepidariorum and the 

 Medicinal spider, as determined by a number of tests, shows that the 

 incident on such grounds is not only plausible but much within the 



1 " The figure intended to represent the spider is larger in proportion to that insect than 

 the mouse is to the unlucky little rodent it is supposed to suggest. The length of the line 

 attached to the tail is much shorter in the sketch than in the original, where it must have 

 been three feet or over, as the web from which it was suspended was woven upon the bot- 

 .torn of a writing desk, and, as nearly as I can remember, in the shape presented, but much 

 larger." Mr. Knott's letter. 



2 Specimens sent to me of the spiders supposed to be identical with the one that caught 

 the mouse, taken from the same desk and from a web of similar construction, were the 

 Medicinal spider. Also, a specimen of a web somewhat similar to the one in which the 

 mouse was entangled, and a description with estimated measurements, of the extensive pro- 

 portions of the original snare, point in the same direction. 



* "A mature male mouse weighed three hundred and fifty-six grams. One half grown 

 would probably weigh about one-sixth to one-fourth of this, say from sixty to ninety grains."- 

 Xote from Dr. Joseph Leidy. 



