10 



Arachnida and Myriopoda 



Family— THEBIDIIDAE. 



The members of the family Theridiidae are sedentary spiders, 

 but the web which they construct is never orbicular. The 

 presence of a comb of bristles on the tarsus of the last leg is 

 a feature distinguishing them from the closely allied Argiopidae 

 (Epeiridae). 



Genus — Latrodectus, Walckenaer. 



Spiders belonging to the genus Latrodectus have the reputation 

 in many countries of being dangerous to human beings and other 



animals ; and there is so much in- 

 dependent testimony on this point 

 that it seems highly probable that 

 the bite of certain species of this 

 genus is more venomous than that 

 of other spiders. 



In New Zealand the bite of the 

 Katipo {Latrodectus hasselti, var. 

 katipo, Powell) is believed to be 

 very poisonous. Latrodectus mac- 

 tans, Fabricius, a species occurring 

 in North America and also in 

 Central and South America, is 

 another species with a bad reputa- 

 tion. The " Malmignatte " (Latro- 

 dectus lS-guttaius, Eossi), a spider 

 which is very common in Southern 

 Europe, has also been accused of 

 being a dangerous species. Bordas 

 states, however, that the effects of 

 its bite are not very serious and 

 cannot cause the death of a human being. He made specimens of 

 the Malmignatte bite his wrist or the ball of his thumb on many 

 occasions, and says that the bite causes redness and slight tume- 

 faction of the skin over an area of about 2-3 centimetres, besides 

 a certain amount of difficulty in moving the fingers, numbness of 

 the palm, stiffness at the articulation of the wrist, violent itching in 

 the region of the punctures, darting pains which disappear at the 

 end of a few hours and return again at intervals, etc. After a few 

 days these symptoms disappear almost completely, and at the end 

 of a week all trace of inflammation has also gone. Dufour, Lucas, 



Fig. 3. 



Latrodectus tredecimguttatus, 

 Rossi, x 2. 



