LIFE-HISTORY OF NOSEMA APIS 219 



Sometimes a planont does not enter an epithelial 

 cell of the gut after having penetrated between the 

 cells, but continues onwards and reaches the body 

 cavity or haemoccel of the bee. There it may 

 remain, or after a short time it may return into 

 the gut. Other planonts, as previously mentioned, 

 penetrate the gut epithelium direct. 



In either case the motile planont becomes quiescent 

 and develops as a trophozoite (Fig. 40, D). After 

 growth has proceeded for a time, the nucleus of the 

 trophozoite divides into two. The body protoplasm 

 divides also, and two daughter forms are produced. 

 These dividing forms are known as meronts or 

 schizonts. There are several variations in the ways 

 by which daughter meronts are produced, but three 

 main types are encountered. The simplest form is 

 that in which the parasite divides into two practi- 

 cally identical parts. The nucleus lengthens and its 

 substance concentrates in the ends, so that it has 

 the appearance of a dumb-bell. The thin strand that 

 connects the two heads gradually separates, and the 

 body substance divides at the same time, so that 

 two new meronts are formed. Meronts may be 

 rounded, oval, or elongate. 



Sometimes a chain of meronts is produced by the 

 incomplete separation of the original two. If the 

 number of succeeding divisions is the same in both 

 of the daughter forms, a chain of an even number of 

 individuals is produced ; but when irregularity occurs, 

 chains of three, five, or more, are produced. This 

 second method of meront formation has not been 

 met with so commonly in Nosema apis in bees in 



