554 proceedings op the academy of [aug., 



Abbreviations. 



AcSl accessory parts of sting. 



Amp ampulla of gland cell. 



AnlP anterior portion of articular membrane. 



ArtM articular membrane. 



Can canal. 



CanTu canal of chitinous tube. 



Ch chitin. 



CIS clear spot in cytoplasm of cell. 



DDph dorsal diaphragm. 



ECan end of canal. 



FC fat cell. 



GIC gland cell. 



Cflo globule of cell. 



Cfr groovelike indentation in chitin forming canal. 



H heart. 



Hr hair. 



HrS hair socket. 



Hyp hypodermis. 



HypC hypodermal cell. 



Lint large intestine. 



M muscle to move sting. 



Mai Malpighian tubules. . 



CE oenocyte. 



PoatP posterior portion of articular membrane. 



RadStr radial streak of ampulla. 



SInt small intestine. 



St '. sting. 



T trachea. 



Tu chitinous tubes of gland cells. 



TrA transparent area in ampulla. 



VDph ventral diaphragm. 



a to / of figure 2. — a, small barbed hairs; b, small spinelike hairs; c, groovelike 

 indentations on anterior portion of articular membrane; d, heavy and wide 

 vein of chitin between anterior and posterior portions of articular membrane; 

 e, heavy and narrow vein of chitin in posterior portion of articular mem- 

 brane; /, location of gland cells. 



u to e of figure 4. — a, comparatively thin and almost transparent chitin; 6, 

 narrow, thick and yellow band of chitin; c, thick, semitransparent band 

 of chitin; d, wide, thick and opaque band of chitin; e, thick semitransparent 

 chitin. 



o to 6 of figure 9. — a, hypodermal cells, which later become gland cells, now 

 broken loose from hypodermal layer; 6, a later stage of same. 



V, the heavy and wide vein of chitin shown in figure 2, d. 



Fig. 1 has been placed in the text. 

 Plate XIX.— Fig. 2. — Diagram of articular membrane spread out flat under a 

 low-power lens, showing its superficial appearance, and looking through the 

 posterior part {PostP) of membrane at a deeper focus may be seen gland 

 cells and tubes as shown at /. The material used for figs. 2 to 7 inclusive 

 was fresh and was stained slightly with a weak solution of methylin green 



Fig. 3. — A small portion of anterior part (AntP) of membrane from Hb 2 

 showing the groovelike indentations (Gr). X 700. ' 



Fig. 4.— A small portion of posterior part (PostP) of membrane from fig 2 

 lookmg at mner side of chitm with strong transmitted light. Four gland 

 cells {GIC) and many tubes (Tu) are shown. The tubes are twice too 

 wide. X 275. 



Fig. 5. — Large live gland cell, showing its structure. 



Fig. 6. — Large live oenocyte, showing its structure. 



Fig. 7. — Smsill live fat cell, showing its structure. 



