RANDOM NOTES ON NATURAL HISTORY. 



11 



R. I. Entomological Society. 



The subject of the lecture by Professor 

 Packard before the Society ou Wednesday 

 evening, Jan. 14, was " Spiders." There 

 are about eight hundred species linown and 

 described in the New England States, of 

 which the type is our common garden spider. 

 We see its web in the corners of rooms, on 

 shade trees and shrubbery. The male is sel- 

 dom seen. The eyes are eight in number, 

 situated on the top and front of tlie head. 

 The jaws are very powerful and contain the 

 poison which is situated in a sac at the base, 

 and is forced through a duct b^?^ pressure 

 when anything is bitten, and forced out into 

 the wound through minute openings at the 

 end of the nippers. The bite is deadlj- to 

 all insects, but there is a question whether 

 it is harmful to the human family. Professor 

 Ileintz, who was considered authority on 

 the subject, having studied them for years, 

 claims that the bite is harmless, having 

 caused them to bite him in different parts 

 of the bodj' at various times with no evil 

 results. 



But there is a species of large ones (Lath- 

 odectes) in Alabama, which has been re- 

 ported as having caused the death of a num- 

 ber of persons. In Italy it is a common be- 

 lief among the ignorant that the bite of the 

 tarantula produces an uncontrollable desire 

 in persons bitten to dance until the}' drop 

 from sheer exhaustion. 



One species of the tarantula, genus Ly- 

 cosa, is quite coraaion with us, is large and 

 black, but spins no web. It lives in holes 

 in the ground aiid has the art of gathering 

 small leaves and forming a sort of ball, 

 fastening them together with silk, and plac- 

 ing it over the nest as a protection. 



The spinning glands are six in number. 

 The thread is of fluid form until it reaches 

 the air, when it hardens into silk, and is 

 formed by each spinnaret uniting its con- 

 tents with the aid of the feet, thus forming 

 a single thread. In October, the young of 

 our common s[)inning spiders can be seen 

 floating over fields and gardens, often at a 

 great height. They stand on their fore legs, 

 elevating the hind body in the air, and draw 

 out the silk with the hind legs, letting it float 

 in the air until there is enough to float them 

 with the aid of a light breeze. 



The trap-door spider, or m3'gale, is found 



in the southwest United Stales. It is very 

 powerful. The trap is made in the ground, 

 with the door flush with the surface, made 

 to open and close by means of a hinge. 



Tourmaline. 



Rhombohkdual : Hardness, 7 to 7.5 ; 

 Gravity, 2.9 to 3.3. Is composed of silica, 

 alumina, and boron, with some magnesia, 

 and perhaps a fraction of iron or lithia, and 

 is one of the most interesting minerals in 

 the world, on account of the facets of ter- 

 mination often varying at opposite ends of 

 a crystal, and the fact that specimens dis- 

 located and curved are not infrequent ; also 

 for the property of dichroism, which is well 

 described in " The Tourmaline," by Dr. A. 

 C. Hamlin, who says : '' Some of the prisms, 

 when viewed parallel to their axes, appear 

 of a splendid crimson hue ; but when the 

 prism is slightly- turned, the red color van- 

 ishes as if b}' magic, and the stone becomes 

 white, or smoky, or green. Other crystals 

 are green when viewed transversely and 

 yellow-brown axially, or dark violet trans- 

 versely and green blue axially." All speci- 

 mens do not, however, possess this prop- 

 erty. 



The high-colored and transparent crystals 

 often present in their length much diversity 

 of color, such as deep red at one end and 

 light pink or white at the other ; or per- 

 haps red and green, with beautiful grada- 

 tions where the colors shade into each 

 other ; while others viewed at the ends, 

 prove to be pink or red at the centre, and 

 green outside, as if the red had been first 

 made and then the green rolled around it. 

 Those found at the Chesterfield, Mass.. 

 localit}', are often of this sort, while those 

 from Paris, Me., are world-renovvned, and 

 exhibit all of these wonderful peculiarities. 

 We must not forget to note also the elec- 

 trical properties, which, when a crystal is 

 heated, are negative atone end, and positive 

 at the other, generally positive at the end 

 with the greatest number of facets, and this 

 state, says Dr. Hamlin, " ma}- be reversed 

 by intense cold." If one of the prisms be 

 broken w'hile in an electric state, excited by 

 heat, the fragments present opposite poles, 

 like artificial magnets. It is shown that, if 

 heated somewhat above 212° Fahrenheit, it 



