792 



THE AMERICAN NATURALIST 



[Vol. XLII 



individual cells from the center to the periphery of the 

 glandular mass. The cells in the main body are sharply 

 defined, being separated from one another by distinct 

 lines of demarcation. Near the margin of the gland it is 

 not so easy, however, to define the contour of the indi- 

 vidual cells, these passing gradually into the regular type 



of hypodermal cells. In this type the nuclei are smaller 

 and the cell outlines are not discernible. In sections of 

 the gland the cells are not uniform in width, due to the 

 fact that the sections pass in the center of some and in 

 the sides of others. The glands of the two segments are 

 about equal in size. In sections that pass through the 

 long axis they are 292 microns in Lepyronia quadrangn- 

 laris, and in A. parallela they are 465 microns. Most of 

 the sections which the writer has made show clear spaces 

 (sp., Fig. 5) between the individual cells. These spaces 

 vary in their appearance in different preparations, and 

 evidently represent artifacts due to faulty fixation, rather, 

 than the normal appearance of the cells. 



In the middle of the glands the cells are high, cylin- 

 drical or cubical. On the margin they are low. In the 

 last instar of the nymphs of A. parallela they are 30 

 microns in height and 18 microns in width in the center 



