THE SOCIAL INSECTS 



recorded. Emerson kept queens of some of the South 

 American species and actually observed that 1,600-7,500 

 eggs were laid in twenty-four hours. One of the species 

 which builds the large steeple-like nests in Africa has been 

 seen to lay 36,000 eggs in twenty-four hours ; this corre- 

 sponds to thirteen million a year. 



The method of sex-determination is different from that 

 of ants, bees and wasps. If the developing sexual cells are 

 stained and examined under a microscope, it is found that 

 those of the female contain an even number of heavily stained, 

 rod-like bodies or chromosomes. The corresponding cells in 

 the male have one less chromosome. Thus as far as sex is 

 concerned, the hereditary constitution of the queen termite 

 may be represented by the symbols AAXX and of the male 

 by AAX. The unfertilised eggs all have the constitution 

 AX, but the sperm may be A or AX. Thus when the eggs 

 are fertilised, females (AAXX) and males (AAX) are pro- 

 duced in equal numbers. 



Termites are one of the groups of insects in which develop- 

 ment up to the adult stage is gradual. This means that there 

 is no grub, nor an immobile pupa enclosed in a cocoon. 

 The individual which hatches from the egg is like the adult 

 except that it is small, has no traces of wings, and is sexually 

 immature. 



It is convenient to use the French terminology for refer- 

 ring to the immature stages, though it is not universally 

 accepted. The form which hatches from the egg is the larva, 

 and it continues to be one in spite of moulting, as long as it 

 has no traces of wings. The nymph resembles the larva but 

 has visible wing-pads. To produce a fully winged adult 

 from the nymph will require several moults, at each of which 

 the wing-pads will get a little longer. 



The soldier is typically without wing-pads, is relatively 



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