572 



E. H. DUSHAM 



DEVELOPMENT OF THE GLANDS 



Mingazzini, in his work on Periplaneta orientalis, found that 

 these gland cells were less developed in the nymphs than in the 

 adult. In such immature stages he found that sections showed 

 only a single layer of cells, between which were observed fre- 

 quently large modified cells. In Blatta germanica these gland 

 cells were first distinguished during the first instar when the 

 nymphs are two days old (fig. 11). At that time some of the 

 normal hypodeniial cells become modified. The nuclei which 

 are deeply stained and densely granular, gradually increase in 

 size still retaining their densely granular appearance. There is 

 also an increase in the amount of cytoplasm around these nuclei, 

 with the result that the adjacent normal hypodemial cells are 

 crowded so that their regular arrangement is somewhat broken. 

 The growth in size of the nucleus and the increase of cytoplasm 

 also cause these cells to project below the level of the normal 



