60 Wisconsin Academy of Sciences, Arts and Letters. 
EXPLANATION OF PLATE IV. 
Fig. 14. Section through two Malpighian tubules at their entrance 
into the mid-intestine, showing the gradual passing over of the large 
cylindrical cells of the mid-intestine into the somewhat flattened cells 
of the Malpighian tubules; mlp, opening of Malpighian tubule into 
mid-intestine; sm, striated intima; nep, nucleus of epithelial cell, 
(x 525.) 
Fig. 15. Longitudinal section through the posterior iliac valve:— 
il, ileum; fr, folds of rectum; ch, chitinous intima of ileum; ep, epi¬ 
thelium of ileum; elm , external longitudinal muscles; him, branch of 
external longitudinal muscles; cm, circular muscles; bo, boundary be* 
tween ileum and rectum, (x 116.) 
