490 NEW YORK STATE MUSEUM 



OS Opening of the spiracle 



p Pleura 



po Peripheral layer of chitin of the caudal spines 



pdc Paired dorsal cavities 



pe Peritreme 



pf^ Prothoracic filaments 



pr Protborax 



ps Pedal setae 



pst Posterior sternal setae 



pt Posterior tergal setae 



pvo Paired ventral cavities 



po! Proximal setae of the labrum 



r Denuded roots 



reo Rectum 



s Spiracle 



sn Sensory spots 



ss Supraspiracular setae 



St Sternal setae 



t Tracheal taenidia 



tr Trachea 



ttr Transverse trax;heal trunk 



V Venter 



vo Ventral cavity 



vh Vacuolated hypoderm^al cells 



vv Ventral border paired ventral cavities 



w Cuticular wedge paired ventral cavities 



x Leaf stalks 



y Scars of shed leaf stalks 



« Larvae 



PI/ATE 20 



View near th'e outlet of the Benwick lagoon, looking' southeast. 

 Photo by J. H. O'omstock 



PLATE ai 



1 Portion of leaf of Nymphaea advena, shiowing eggs of 

 Donacia palmata. Photo by J. G. Needham 



2 Portion of leaf of a sedge, showing the eggsi ~of D'onacia 

 porosicollis 



3 Eggs of Donacia cincticornis 



4 A single egg mass of Donaciapalmata 



PLATE 22 



Underground stem of Nymphaea advena, showing larva* 

 and cocoons of Donacia palmata. Photo by J. O. Martin 



PLATE 23 



Plant of Sparganium androcladlum. Photo by J. G. 

 Needham 



a Summit of the plant with beetle on the leaf. 6 Roots as withdrawn 

 from the water, showing cocoons of Donacia emarginata near 

 the base of the leaves 



