98 
Guide to Arachnida. 
Table-case turns upon him with murderous intent during 
No ‘ 23 ' courtship, as female spiders commonly do. 
Some of the tropical Argiopidae ( Gasteracantha , , 
etc.) have the abdomen hardened and armed with 
long spines. It is believed that these are of ad- 
vantage to the spider by rendering it unpalatable 
to birds. The male of Gasteracantha, which is 
much more retiring in its habits than the female, 
is not furnished with spines. Remarkable illustra- 
tions of protective resemblance are afforded by 
some of the species belonging to this family, 
as, for instance, the Rhodesian species known 
as Caerostris corticosa. In colour and general 
appearance this spider harmonizes with the bark 
of the common Rhodesian thorn- tree, on which it 
is commonly found, and its abdomen is furnished 
with processes resembling the thorns with which the tree is beset. 
The Argiopidae are cosmopolitan in distribution. 
Fig. 63. 
Tarsal-comb of 
the fourth leg of 
Theridion tejpida- 
riorum. 
Magnified. 
(After F. 0. Pick- 
ard- Cambridge.) 
Fam . — Theridiidae . 
These spiders differ but little in 
structure from the Argiopidae, but 
may be readily distinguished from 
them by the structure of the fourth 
leg, the terminal segment of which 
bears a comb of setae (fig. 63). 
A few of the species are remarkable 
in that they construct no web. The 
family is very numerous in species, 
and has a wdde distribution. 
The genus Lathrodectus is, per- 
haps, the most noteworthy of the 
Theridiidae. Several of the species 
have the reputation of being ex- 
tremely poisonous, and numerous 
accounts of the effects of their 
bite have been published. The 
abdomen in the poisonous species 
is marked with conspicuous red stripes or spots. A coloured draw- 
ing of the well-known European species ( Lathrodectus tredecim- 
guttatus) is exhibited in Table-case 23. 
A Theridiid Spider 
(Lathrodectus tredecim - gutta 
tus), x 2. 
