24 CATEEPILLARS AND THEIR MOTHS 



enters the mieropyle of the egg, and this now fertile 

 egg is laid by the ovipositor on a twig, leaf, or other 

 safe place to which it is fastened by a sticky fluid 

 which is forced out of the ovipositor with it and har- 

 dens as glue does. All moths, however, do not fasten 

 their eggs to a support, but some drop them anywhere 

 on the ground, or in our boxes. Such moths usually 

 lay many eggs, and we had one Arctia which dropped 

 in one of our boxes 1395 tiny yellow eggs, so small 

 that it was a task to count them. We speak of eggs 

 being laid " in a safe place," but they are by no means 

 always safe. Birds often find them and eat them, and 

 some parasitic flies pierce the shells with their ovi- 

 positors and lay their eggs inside the moth eggs. In 

 this case the fly-larvse devour the contents of the 

 moth eggs, and flies hatch instead of caterpillars. 

 Egg-laying continues for several nights, the number 

 of eggs laid being greatest on the first night, usually, 

 and growing smaller each night after. We had one 

 moth which laid eggs for ten nights, and this is the 

 greatest number our records show. It sometimes 

 happens that a captured moth will not oviposit the 

 first night or even the second, but afterward lays a 

 goodly number of fertile eggs. 



Probably out of doors moths usually mate before the 

 female begins ovipositing, but in confinement it often 

 happens that males are not at hand, and the pl-essure 

 of the ripest eggs compels egg-laying. In such cases 

 mating has sometimes taken place after one or two 

 nights of egg-laying, when males have emerged in our 

 cages or been attracted from out of doors. Some 

 moths are polygamous. 



