30 



SCIENCE. 



[Vol. XXI. N:> 520 



ence c-an be justiSed in seekinK unaided to enlighten the world 

 upon these questions. 



The fact is that a large part of the literature relating to the 

 palEeolithic and ice-age questions is so hopelessly embarrassed 

 with the blunders and misconceptions belonging naturally to the 

 initial stages of the investigation that it is but little more than a 

 stumbling-block to science, notwithstanding the possibility that 

 there may be many hints of truth in what has been writ'en. It 

 would appear to be a more collofsal ta--k, however, to discover 

 these hinis of truth in the literature of today than to wrench 

 them afresh from the rocky tomes of nature. 



In conclusion, I would add that if there was, as is claimed, an 

 ice-age man or at any time a palaeolithic man in eastern America, 

 the evidence so far collected in support of these propositions is so 

 unsatisfactory and in such a state of utter chaos that the investi- 

 gation must practically begin anew. That it will begin anew is 

 rendered practically certain by the facts that geologists are now 

 showing a decided disposition to take up that part of the work 

 naturally belonging to them; and that primitive forms of art in 

 stone are now for the first time receiving the critical attention 

 necessary to make them available in a scientific discussion. Thus 

 it appears that the suggestion embodied in the title of this com- 

 munication may not be wholly unwarranted and inappropriate. 



THE NEST OF THE TRAP-DOOR SPIDER. 



ET D. GLETTELAND, SAN DIEGO, CALIFORNIA. 



The trapdoor spider {Mygale henzii Girard) is widely diffused 

 in California. While wandering over the Mesa (table lands), just 

 back of this city a few months ago I was struck by the great 

 number of their nests in favorable localities. In the adobe land 

 hillocks are numerous ; in fact, in many places, they are as thick 

 as the ground will permit. They are about a foot in height, and 

 some three or four feet in diameter. These hillocks, which are 

 an interesting formation in themselves, are selected by the spiders, 

 apparently, because they afford excellent drainage, and cannot 

 be washed away by the winter rains. Their stony summits are 

 often as full of spiders' nests as they well can hold. These sub- 

 terranean dwellings are shafts sunk vertically in the earth, ex- 

 cept where some stony obstruction compels the miner to deflect 

 from a downward course. These shafts are from five to twelve 

 inches in depth, and from one-lialf to one and a half inches in di- 

 ameter, depending largely upon the age and size of the spider. 



When the spider has decided upon a location, which is always 

 in clay, adobe or stiff soil, he excavates the shaft by means of the 

 sharp horns at the end of his mandibles, which are his pick and 

 shovel and mining tools. The earth is held between the mandi- 

 bles and carried to the surface. When the shaft is of the required 

 size, the spider smooths and glazes the wall with a fluid which is 

 secreted by herself. Then the whole shaft is covered with a 

 silken paper lining, spun from the animal's spinnarets. 



The door at the top of the shaft is made of severaljalternate layers 

 of silk and earth and is supplied with an elastic and ingenious 

 hinge, and fits closely in a groove around the rim of the tube. This 

 door simulates the surface on which it lies, and is distinguishable 

 from it only by a careful scrutiny. The clever spider even glues 

 earth ajid bits of small plants on the upper side of bis trap-door, 

 thus making it closely resemble the surrounding surface. 



The spider generally stations itself at the bottom^of the tube. 

 When, by tapping on the door, or by other means, a gentle vi- 

 bration is caused, the spider nzns to the top of his nest, raises 

 the lid, and looks out and reconnoitres. If a small creature is 

 seen, it is seized and devoured. If the invader is more formid- 

 able, the door is qviickly closed, seized and held down by the 

 spider, so that much force is required to pry it open. Then, 

 with the intruder looking down upon him, the spider drops to 

 the bottom of his shaft. 



A young friend of mine has spent much time lately watch- 

 ing and investigating the operations of this sp.ider. He found 

 by many experiments — all with the same result — that when the 

 door of his nest is removed, the spider can renew it five times — 

 never more than that. Within these limitations, the door torn 



off in the evening was found replaced bya new one in the morn- 

 ing. Each successive renewal showed, however, a greater pro- 

 portion of earth, and a smaller proportion of silk, until, finally, 

 the fifth door bad barely enough silk to hold the earth togeth- 

 er. The sixth attempt, if made, was a failure, because the spin- 

 narets had exhausted their supply of the web fluid. When the 

 poor persecuted spider finds his domicil thus open and defence- 

 less, he is compelled to leave it, and wait until his stock of web 

 fluid is renewed. 



From forty to fifty cream-colored spiderlings are hatched from 

 the yellow eggs at the bottom of the nest. When these have 

 attained only a fraction of their full size — before they are half 

 grown — their affectionate mother drives them out into the world 

 to shift for themselves. After a brief period of uncertainty, they 

 begin active life by making nests, each for itself, generally close 

 to " the old homestead," sometimes within a few inches of it. 

 These nests are always shallow and slender, and are soon out- 

 grown. When the spider attains its full size it constructs a larger 

 nest. 



The spider is seldom seen outside of its nest, which it rarely 

 leaves — during the day, at least, and then only for a few minutes, 

 and for a short distance. Upon any alarm, it hastens to its nest, 

 lifts the door, which quickly springs back into its place, and is 

 held donn by the householder until the alarm has subsided. 



I now have a large nest, containing a mother and her yellow 

 spiderlings, which I am carefully watching and studying. 



BALANCES OF THE PERUVIANS AND MEXICANS. 



BY WALTEH HOUGH, WASHINGTON, DC. 



The employment of weights and measures among the existing 

 uncultivated peoples is a subject upon which but little information 

 has been gathered. The following instances of the use of balances 

 and weights in pre-Columbian America are interesting from an 

 archaeological point of view. 



In the Archaeological Museum of Madrid there aie two pairs of 

 balances and four beams, from sepulchres of the Yncas at Pachaca- 

 mac, Peru. The possession of this probably oldest weighing ap- 

 pliance by the ancient Peruvians is very curious. A flat strip of 

 bone suspended edgewise by a cord midway forms the beam. To 

 the eiids of the beam are hung, by short cords, slings of net- work 

 made of fine thread, the free edges being strengthened by cord. 



One of these balances is plain, while the beam of the other is 

 elaborately fretted and engraved with circles-and-dots, and curves 

 outlining the fretted spaces. Red paint has been rubbed in these 

 incisions. The long suspending cord is strung alternately with a 

 row of small beads of turquoise and red and white shell and a 

 large, flat, oblong piece of shell pierced through the axis. The 

 string is terminated by the figure of a bird and a fret ornament 

 of shell representing a seated human figure with head-dress. 

 Three small pendants of beads and shell hang below this and the 

 whole forms an ornate and striking specimen. 



One of the beams exhibited is of bone, ornamented with circles- 

 and-dots, so regular, that they would appear to indicate the use 

 of another instrument of precision, the compass. 



Dr. Brinton has ascertained that the weights were small stones.' 

 It would seem that, for the purpose of equalization of weights, 

 the equilibrium of the beam being gauged by the eye, these bal- 

 ances are quite accurate. They are in perfect order at the present 

 time. 



In the Mexican collection at the Columbian Historical Exposi- 

 tion in Madrid there are two spherical objects of lasalt, from the 

 ancient Tarascos of Michoacan, which Dr. Troncoso, director of 

 the Mexican National Museum, believes are weights. He sup- 

 ports this view by stating that at present the Indians use similar 

 stone weights on their imperfect balances, which are formed of 

 two small trays of wood, each suspended by three strings from 

 the end of a wooden beam, which is balanced by a cord fastened 

 at the middle. 



It is possible that the use of the balance will be found to have 

 been more extensive in America than is suspected. 



' Proceedluga Numismatic and Antlquariau Society, Ptiiladelphla, 1891. 



