406 FOOD OF INSECTS. 



than a grain of sand, are so fine that four millions of 

 them would not equal in thickness one of the hairs of 

 his beard. Of such tenuity it is utterly beyond the 

 power of the imagination to conceive : the very idea over- 

 whelms our faculties, and humbles us under a sense of 

 their imperfection. — Of the probable accuracy of this 

 calculation you may any day in summer convince your- 

 self, by taking one of the large field spiders (Aranea 

 Diadema, L.), and after pressing its abdomen against a 

 leaf or other substance, so as to attach the threads to the 

 surface — the same preliminary step which the spider 

 adopts in spinning — drawing it gradually to a small di- 

 stance. You will plainly perceive that the proper thread 

 of the spider is formed of four smaller threads, and these 

 again of threads so fine and numerous, that there cannot 

 be fewer than a thousand issue from each spinner ; and 

 if you pursue your researches with the microscope, you 

 will find that precisely the same takes place in the mi- 

 nutest species that spins. — You will inquire what can be 

 the end of machinery so complex ? One probable rea- 

 son is, that it was necessary for drying the gum suffi- 

 ciently to form a tenacious line, that an extensive surface 

 should be exposed to the air ; which is admirably effected 

 by dividing it at its exit from the abdomen into such nu- 

 merous threads. But the chief cause, perhaps, is the 

 occasion (hereafter to be adverted to) which the spider 

 sometimes has to employ its threads in their finer and 

 unconnected state before they unite to form a single one^ 

 — The spider is gifted by her Creator with the power of 

 closing the orifices of the spinners at pleasure, and can 

 thus, in dropping from a height by her line, stop her 



