136 PERl'ECT SOCIETIES OF IN.SECTS. 



the larger animals, that numerous differences, both as 

 to the form and relative proportion of parts, occur 

 continually. The cause of these differences we can- 

 not always ascertain ; yet in many instances they may 

 either be deriv^^d from the nutriment w hich the embryo 

 receives in tlie womb, or from the greater or less di- 

 mensions or higher or lower temperature of that or- 

 gan — a case that analogically would not be very wide 

 of that of the grub orcndiryoof a bee inclosed in a cell. 

 Some of the differences in man I now allude to, may 

 often be caused by a particular diet in childhood ; a 

 warmer or a colder, a looser or a tigliter dress, or the 

 like. Thus, for instance, the Egyptians, who went 

 bare-headed, had their skulls remarkably thick; while 

 the Persians, who covered the head with a turban or 

 mitre, were distinguished by the tenuity of theirs. 

 Again, the inhabitants of certain districts are often re- 

 markable peculiarities of form, which are evidently 

 produced by local circumstances. 



The following reasoning may not be inapplicable to 

 the development or non-development, according to 

 their food and habitation, of the ovaries of these insects. 

 An infant tightly swathed, as was formerly the custom, 

 in sAvaddling bands, without being allowed the free play 

 of its little limbs, fed with unwholesome food, or un- 

 cherished by genial warmth, may from these circum- 

 stances have so imperfect a development of its organs 

 as to be in consequence devoted to sterility. When a 

 cow brings forth two calves, and one of them is a female, 

 it is always barren, and partfUics in part of the charac- 

 ters of the other sex'. In this instance, the space and 

 food that in ordinary cases are appropriated to one, are 



* See J. Hunter's Treaihc on certain Faits of ike Animal CEconuin^^ 



