PAR'l'HENOGENETIC TENDENCY IN MELANOGERA MENIPPE. 283 



paired or not the female of maia lays freely, but more eggs 

 were, on the whole, laid by females placed with males. 



It was noticed that the eggs of one of the paired moths were 

 very exceptionally slow in shrivelling, and on this account it 

 was thought that possibly copulation had occurred and more 

 or less normal development was taking place. There was 

 ver}" little shrivelling in five weeks after laying, although 

 unfertilised eggs are obviously indented after a period of 

 fourteen to twenty days. After the eggs had been laid seven 

 weeks, shrivelling had become more mai'ked, and seventy-five 

 eggs were opened and examined with a hand-lens. In eighteen 

 eggs a whitish granular lump or lumps on the periphery of 

 the yolk could be seen. An examination with the microscope 

 showed that these consisted chiefly of dense clusters of needle- 

 shaped crystals. The crystals dissolved in 50 per cent, 

 hydrochloric acid. They doubtless ai'ose by the concentration 

 of the salts in solution in the egg through evaporation, and 

 their formation appears to depend largely on the slowness 

 of evaporation. In rapidly drying eggs the crystals were not 

 found. In 150 eggs from several unpaired maia females only 

 one egg was found containing such ciystals. 



The microscopic examination of the contents of the eggs 

 which so successfully resisted desiccation revealed no definite 

 sign of segmentation. 



Without much more investigation it cannot be said whether 

 the formation of such crystals was in any way connected with 

 an unsuccessful attempt at development after copulation. An 

 egg stimulated by contact with the male fluid, even without 

 actual fusion of nuclei, might be able conceivably to resist 

 desiccation much better than an unstimulated egg. The power 

 of resisting desiccation is undoubtedly a vital act not directly 

 explainable in ordinary chemical and physical terms. 



With respect to the remaining six paired moths, about fifty- 

 eggs from each — that is, about 800 in all — w^ere examined, and 

 only six exhibited any obvious crystal formation, and even in 

 these it was less marked than in the case above described. 

 These eggs began to shrivel in about twenty days. 



VOL. 3, PART 2. 20 



