Since the days of earliest mythology the spider and his web have been a favorite figure of speech. Here we see interesting specimens of these spiders, which inhabit all quarters of the world and grow to their largest size in the tropics. The arachnidium, wherewith they spin the barely visible silky threads which are used for their webs, have been closely studied by inventors and utilized in their models for reproducing this function mechanically. The delicate webs which these gossamer threads form are at once the spider's home and his means of catching his prey. Commercially, they have been used as cross-lines in telescopes, and even utilized for textile fabrics; but in the latter instance, only as curious. The male spider is larger than the female, whose eggs are numerous and usually enveloped in a cocoon. Although the spider's bite is fatal to other insects, it does not affect mankind.