EGGS NOT FERTILIZED , 85 



of the year and the eggs requiring fertilization ("winter 

 eggs") are produced at other seasons. In some cases the 

 mothers may differ, some forming both summer and winter 

 eggs and others parthenogenetic eggs only. 



Furthermore, there is occasional parthenogenesis even 

 among forms where fertilization is the rule. For example, 

 it is known that the sj)orophyte of ferns may sometimes 

 develop from cells of the gametophyte without fertilization. 



3. The Case of the Honey Bee. Perhaps the best known 

 case of parthenogenesis is that of our common bees. The 

 queen, who is the one perfect female of the hive, receives 

 a large supply of sperms at mating. This is stored in a 

 sac opening into the duct along which eggs come from the 

 ovaries on their way outwards. It is believed that the 

 queen can control the sperm supply in such a way that 

 eggs may pass to the surface either with sperm or without. 

 In doing this, the queen is doubtless controlled by 

 temperature, food, the conditions in the hive, the size of 

 the cells provided for the eggs, etc. When she forces out 

 sperms on the passing eggs and they are fertilized, they 

 develop into the workers (females). If the eggs are not 

 fertilized, they develop into the males (drones). While 

 the workers are females, they are not perfectly developed 

 females as the queen is. Apparently any fertilized egg 

 may develop a queen if the larva is specially nourished to 

 that end. Observers claim that the workers may lay 

 unfertilized eggs that may develop. There are many cases 

 of parthenogenesis found among the kindred of the bees, 

 the other social insects, such as bumble bees, wasps, ants, 

 etc. Some of these are as interesting as the case of the 

 honey bee, but they are not so well known to the general 

 student. 



4. Hydatina, the Rotifer. This little "wheel animalcule," 

 of about the grade of development shown by worms, is 

 found in stagnant water. Its life history has been very 

 well studied. There are three kinds of eggs produced, 



