420 



CRUSTACEOLOGY. 



Arachni- a fright dropping down their thread and returning in 

 des - a few minutes to make a fresh trial by feeling. When 

 -ijii ¥ -b_i" ^^ p art j es gjg we J[ assured of the sex they have to 

 deal with, the approaches of their feet in order to feel 

 are more frequent ; confidence takes place, and amo- 

 rous dalliance ensues. " We cannot," says Lyonhet, 

 " but admire how careful they are not to give them- 

 selves up blindly to, or venture on, an imprudent step 

 which might become fatal to them." 



As to the employment of spiders threads in place of 

 silk, Bon of Languedoc, about eighty years ago, made 

 a pair of stockings and gloves from the threads of some 

 species of spider ; they were of a fine grey colour, and 

 nearly as strong as those of common silk : on this dis- 

 covery, he published a dissertation. Reaumur, who was 

 appointed by the Royal Academy to examine into the 

 merits and probable advantages which might arise from 

 such a manufacture, urged the following objections 

 and difficulties against it, which are published in the 

 Memoirs of the Academy for the year 1710: — The na- 

 tural fierceness of the spiders renders them unfit to 

 be bred and kept together. Four or five thousand 

 being distributed in cells, fifty in some, one or two 

 hundred in others, the big ones soon killed and eat 

 the smaller ones, so that in a short time there were 

 scarcely above one or two left in each cell ; and to this 

 inclination of devouring their own species, he attri- 

 butes the scarcity of spiders when compared with the 

 vast number of eggs they lay. He affirms also, that 

 the web of the spider is inferior in strength and lustre 

 to that of the silk worm, and produces less of the ma- 

 terial fit for use. The thread of the spider's web, he 

 gays, can only bear a weight of two grains without 

 breaking ; and the bag sustains the weight of thirty- 

 six grains : the thread of a silk worm will bear two 

 drams and an half, so that five threads of the spider 

 are necessary to form a cord equal to that of a silk 

 worm ; as it would be impossible to apply these so close- 

 ly together as to avoid leaving any empty space be- 

 t ween from which the light would not be reflected, and 

 consequently would throw out much less lustre : this 

 was noticed at the time the stockings were presented 

 to the society by M. de la Hire. He further remarks, 

 that spiders afford less silk than silk worms : the lar- 

 gest bags of the latter weigh four grains, the smaller 

 three grains ; so that two thousand three hundred and 

 four worms produce a pound of silk. The bags of a 

 spider weigh about one grain ; when cleared of the 

 dust and filth they lose two thirds of that weight. The 

 work of twelve spiders, therefore, only equals that of 

 one silk-worm ; and a pound of silk will require at 

 least twenty-seven thousand six hundred and forty- 

 eight spiders. But as the bags are solely the work of 

 the females, who spin them to deposit their eggs in, 

 there must be kept 55,2Q6 spiders to yield one pound 

 of silk ; yet this will apply to the good ones only ; 

 those spiders in gardens most commonly scarcely yield- 

 ing a twelfth part of the silk of the domestic kinds. 

 Two hundred and eighty, it seems, would not produce 

 more than one silk-worm ; six hundred and sixty-three 

 thousand, five hundred and fifty-five of them, would 

 scarcely yield a pound. 



From the above memoir it seems that the manufac- 

 ture of silk from the European spiders would be at- 

 tended with more trouble than profit ; yet the webs of 

 the large species inhabiting the tropics might probably 

 be turned to good account, as we learn from Sir George 



Staunton's embassy to China, who, when speaking of Arachni- 

 the Java forests, says, " in some open spots were found des - v 

 webs of spiders even with threads of so strong a tex- — ' Y 

 ture as not easily to be divided without a cutting in- 

 strument; they seemed to render feasible the idea of him 

 who, in the southern provinces of Europe, proposed a 

 manufactory of spider's threads, which was so very ri- 

 diculous to the eyes of those who have only viewed the 

 flimsy webs such insects spin in England." 



Having given an account of the animals which com- 

 pose tliis family, as far as relates to their general history 

 and economical uses, we shall proceed to define the 

 genera, as given in the works of Walckenaer, Lamarck, 

 and Latreille, the characters being deduced from the 

 positions of the eyes, length of the different feet, figure 

 and structure of the maxillae, &c. ; and when describ- 

 ing the species, we shall notice any peculiarities in their 

 form, structure, or economy. 



Their use in the economy of nature appears to be 

 principally that of preventing the two great increase 

 of other bisects. 



I. Feet not formed for leaping. 



Genus XXVI. Mygale, Latr. Walck. Aranea, 26. Mi- 

 Lin. Fab. Lam. OHv. GALE- 



Labium very small and quadrate, inserted under the 

 base of the maxillae. 



Palpi attached to the apex of the jaws. 



A. The nails of the tarsus with few very obscure or 

 no teeth on the under side. 



* Mandibular without any apical rostellum ; the un- 

 der part of the last joint of the palpi and tarsi with a 

 hairy scopula. 



Sp. 1. Avicularia. Body covered with long and thick Avicularia. 

 black hair ; apex of the tarsi and feet rust coloured ; 

 tarsi broad ; nails not exserted. 



Aranea avicularia of Linne and Fabricius. 



Aranea hirtipes, Fabricius, Ent. Syst. torn. ii. p. 420. 



Mygale avicularia, Latreille, Walckenaer. 



Inhabits South America, where it is well known un- 

 der the names Araignee aviculaire, or bird-catching spi- 

 der. Of its natural history we know nothing ; it is 

 the largest species discovered, being often found with 

 a body as large, or even larger, than a goose's egg. It 

 is said to spread a strong web between the trees in 

 woods, in which it takes small birds as weU as insects. 

 The male's parts of generation are globose. 



Sp. 2. Cancerides. Brown and hairy, the under part Ganceride* 

 of the abdomen, with the breast, blackish. 



Mygale cancerides, Latreille. 



Inhabits the island of St Domingo, where it is called 

 araignee-crabe. The genitalia of the male are pro- 

 duced into a horny-arched nail, the apex compressed, 

 the foot-stalk a little longer than in the foregoing species, 



Sp. 3. Blondii. Covered with rust-coloured hair; Blondii,. 

 the basilar joint of the tarsi (especially of the posterior 

 feet) with visible black spines. 



Inhabits Cayenne. 



Mygale Blondii, Latreille. 



Mygale de la Blond, Walckenaer. 



Described and figured in the genera Crustaceorum et 

 Inseclorum of Latreille, (vol. i. tab. 5. fig. 1.) and in 

 Walckenaer's work, p. 4. The genitalia of the male 

 are somewhat conic and thick, the apex laterally exca- 

 vated. 



Sp. 4. Fasciafa. Abdomen with a broad greyish Fasciata* 

 longitudinal band, with the margins wSiched or sinu- 

 ated. 



