572 



TV RAJ AST [Vol. XLI 



There is no indication of a vestige of these glands, such as Gilson 

 found in Limnoyhilus rhombicus, one of the Trichoptera. 



The Conducting Division. — The conducting portion of the silk 

 glands is Y-shaped, with a median stem and branches pointing 

 caudad; each branch joins the thoracic portion on its respective 

 side of the body. The press commences at the juncture of the 

 two branches. The entire conducting portion is very short, being 

 wholly confined to the labium. In cross section the branches are 

 seen to be composed of a number of cells surrounding a small lumen 

 (PI. 3, fig. 25). The nuclei are oval to rounded in shape — never 

 branched. Posteriorly the cells are colunmar and contain elongated 

 nuclei, but anteriorly the cells become fiattened (PI. 3, fig. 30). 

 There is thus formed an enlarged lumen at the anterior end of 

 each branch of the conducting tube. Also by the increased radial 

 diameter of the posterior cells the amount of "gres" or "gum" 

 that can pass forward is regulated (PI. 3, fig. 30). 



The cuticular lining of these branches forms chitinous folds 

 or ridges which are not perfect spirals but appear as incomplete 

 rings. rPl. 3, figs. 25, 29 and 30, in). 



The Press.— Although the internal disposition of the silk glands 

 \\a. faniilar to the earlier anutoTui^ts, nothing was known regard- 



lonnati.ui .4' th.' ^ilk tliivad h u..^ not till thr iiPp,!n..nt unik. 

 nfCilM.,, and Hlaiu-ihar iIh- iniiiui.- --iriu miv tlii. <.ruan in Leo- 

 defined. 



