FECUNDITY OF INSECTS AND FISHES. 47 



deposits two eggs; while a single plant-louse (Aphis), 

 as we mentioned before from Reaumur, may be the 

 living progenitor of 5,904,900,000 descendants, and 

 the queen of the warrior white ants ( Termes hdlico- 

 sus, Smeathm.), produces 31,536,000 eggs in one 

 year. 



We may illustrate this subject by an extract exem- 

 plifying the proportionate fecundity of the animal king- 

 dom in general. ' Compared with the rest of ani- 

 mated nature,' says Dalyell, ' infusion animalcula are 

 surely the most numerous: next are worms, insects, 

 or fishes; amphibia and serpents, birds, quadrupeds; 

 and last is man. The human female produces only 

 one at a time, that after a considerable interval from 

 birth, and but few during her whole existence. Many 

 quadrupeds are subject to similar laws; some are 

 more fertile, and their fecundity is little, if at all, in- 

 ferior to that of certain birds, for they will produce 

 ten or twenty at once. Several birds will breed fre- 

 quently in a year, and have more than a single egg 

 at a time. How prodigious is the difference, on de- 

 scending to fishes, amphibia, reptiles, insects, and 

 worms! Yet among them the numbers cannot be 

 more different. According to naturalists, a scorpion 

 will produce sixty-five young; a common fly will lay 

 144 eggs; a leech,. 150; and a spider, 170. I have 

 seen a hydrachna produce 600 eggs, and a female 

 moth 1 100. A tortoise, it is said, will lay 1000 eggs, 

 and a frog 1 100. A gall insect has laid 5000 eggs; 

 a shrimp, 6000; and 10,000 have been found in the 

 ovary, or what is supposed to be that part, of an as- 

 caricles. One naturalist found above 12,000 eggs 

 in a lobster, and another above 21,000. An insect 

 very similar to an ant [Midilla?) has produced 80,000 

 in a single day; and Leeuwcnhoeck seems to compute 

 four millions in a crab. Many fishes, and those 

 which in some countries seldom occur, produce in- 



