366 ERNEST WARREN. 



Fig. 89. — x 600. Vertical section through an abdominal spiracle and 

 tracheal tube of the larva. An actual perforation was not demonstrated. 

 Note the peculiar large cells forming the wall of the trachea and the 

 huge secretory cells in contact with the hypodermis. 



Fig. 90. — x 600. Median vertical longitudinal section of the larva 

 through the anus and a peculiar eversible organ with tall glandular 

 cells (gl. ep. e. o.). Compai-e anal eversible organ (a. e. o.) in fig. 92. 



Fig. 91. — x 450. Transverse section throvigh larva in the plane of 

 the eversible organ. 



PLATE XXI. 



Fig. 92. — X 70. Semi-diagrammatic view of a median vertical longi- 

 tudinal section of the larva. Note that the abdominal ganglia are 

 drawn forward and do not lie in their appropriate segments; e.g. the 

 eighth ganglion {g. 8) lies in abdominal segment VI. The mandibular 

 commissure (m. c.) is seen. The condition of the imago is foreshadowed 

 in the larva by the character of the alimentary and nervous systems, 

 which are, however, less specialised. 



Fig. 93. — x 85. Transverse section through the abdominal region 

 of the larva. Note the entrance of a Malpighian (e. ml.) tube into the 

 gut, and the exudatory organs (ex. o.). Tracheal tubes (Z. t.) are 

 apparently in the course of formation. 



