324 



N. E. McINDOO 



In these five sections of a 19-day-old pupa 22 pores and 28 large 

 sense cells (fig. 17, SC), besides several smaller nuclei (SCNuc^) 

 were counted. 



In the leg of a 19-day-old pupa the hypodermis (fig. 17, Hyp) 

 is never any thicker beneath the pores than elsewhere in the 





Fig. 17 Combination drawing reconstructed from five consecutive cross sec- 

 tions through femur of third leg of a worker pupa 19 days old. The pores and 

 chitin are drawn diagrammatically and the hair (Hr) with its mother cell {HypNuc') 

 were taken from a similar section of a 17-day-old pupa. The other parts were 

 drawn with the aid of a camera lucida. This shows the internal anatomy of group 

 6. Hi^p, hypodermis; HypNuc, hypodermal nucleus; HypW, inner hypodermal 

 wall or remains of basal membrane; NB, nerve branch; Neu, neurilemma; Tn, 

 tsenidia of trachea; Tra, trachea. X 465. 



leg, and even at this age it is thin and sometimes nearly wanting. 

 Its small nuclei (fig. 17, HypNuc) are widely separated and 

 the hypodermal cell walls (fig. 19, HypCW) are never distinct, 

 but appear as an indefinite mass of minute lines, which are rep- 

 resented in most of the drawings by dots. In the legs of more 



