FORM, GROWTH, AND CHANGE 47 



Oes 



-VNT 



8. 



g. 



10 



FIG. 25. 



A, Internal Anatomy of Male Dragon-fly (Aeschna). Heart (ht) displaced to right, food-canal (oes, 

 gullet ; cr, crop ; mg, stomach ; hg, intestine ; an, anus ; mp, kidney-tubes) displaced to left ; 

 VT, visceral air-trunks ; DT, right dorsal, and VNT, right ventral air-trunks (left ones re- 

 moved) ; sp, spiracles ; as, air-sacs ; 2 8, nerve-ganglia ; is, right testis (the left removed) ; 

 va, vas deferens. x 2 \. B, Tracheal System of Larva of Dendroaeschna, Vr, visceral remnant ; 

 TA, thoracic anastomosis ; ps, thoracic spiracular tube ; al lt al 2 , trunks of wing-rudiments ; 

 Vc, visceral crossing; p z p, trunks if legs; ht, air-tubes of heart; R, tubes from rectal gills 

 (" branchial basket ") ; i 10, indicate position of abdominal segments. Other references as in 

 A. x 6. From Tillyard, " Biology of Dragon-flies ". 



