104 RECORDS OF TUE AUSTRALIAN MUSEUM. 



Genus Blakistonia, Hogg. 



Blakistonia aukea, Hogg. 



(PI. xiii., Hg. 8, PI. xiv., fig. 6, and PI. xv., fig. 7.) 



Blahistonia anrea, Hogg, Proc. Zool. Sue., 1902, p. 182, pi. xiii., figs. 1 and 



2, and text figs. 25b-e. 



Ohs. — Judged by tlie mimbei' of spei;inien,s collected, and tlie wide 

 range of localities from which tliey were obtained, this is the commonest 

 Ctenizid in South Australia. Younger specimens are much blighter than 

 the more aged examples. In some specimens the upper suiface of the 

 abdomen (female) is sprinkled with groups of very dark spots which when 

 viewed by the naked eye, and in spirit, have the ajipearance of chevi-ons. 



Blakistonia dtiren, Hogg, is the common Ctenizid of the Adelaide 

 Plains. Here it attains its largest size, and the nests as figured are closed 

 by lids which may attain the size of 2| cm. in diameter. 



In favourable situations they are very common. In uncultivated 

 land between Adelaide and the sea there are places where several can be 

 found to the square yard (PI. xiii., fig. 8), and the whole Blakistuiiia pop- 

 ulation of the plains must be immense. The economic value of this spider* 

 ill such great numbers ma}' be easily imagined when we consider that its 

 nocturnal habits enable it to capture larval locusts and dispose of a great 

 number. 



In the cultivated lands the tendency- of the frequent disturbance is to 

 drive the spiders to the shelter of the fences, and in these positions we find 

 tliem largely along the highways leaving tlie city in every direction. 

 Plantations, and especially under ])ine ti'ees, are favorite spots, but they 

 are often found on hard, much frequented paths. In wet weather the 

 partial filling up of the tube with water does not seem to inconvenience the 

 spider much, and at the back of the Port River, and the reed beds, 

 Adelaide, specimens are found in great abundance in ground that may be 

 submerged for days together. 



In the summer, at any rate on the plains, the spidei- seals its door 

 down by a collar of web reaching from the side of the tube to the margin 

 of the door. This it does to prevent dessication from the aii- and to pro- 

 tect itself against the parasitic wasj)S which occasionally use it as food for 

 their larvse. That this happens is made certain by the occurrence of pupa 

 cases in the empty bujTow. At the approach of autumn the nests are 

 unsealed and the lids can be lifted as before. The collar, however, remains 

 as evidence of its having been sealed down. 



The male is rarely found in the nest. Most of those found have 

 been collected under stones in cold, wet wintiy weather. About A\nil 

 the egg bag is prepared and the eggs laid ; the bag is of white silk of a 

 long recttangular form like an ordinary pillow, and is suspended from 

 the sides of the tube by diagonally opposite corners. The height, in one 

 cast, was 2 inches, and the peculiar way of suspending it allows the spidei- 

 to pass up and down the tube. In June, one of the wi'iters [R.H.P.] found 

 the bag empty and lying detached in the bottom of the tube with first 

 casts inside it ;iii(l the second on the suiface. In the nest, with the mother 



