PLATES. 



Prostenium terminating in 



prosternal process. 

 Episternum of prosternuni. 

 Episternnm of mesosternuni. 

 Epimeron of mesosternuni. 

 Metasternum. 



12. Wing of metasternum. 



13. Episternum of metasternum. 

 Coxal cavities. 

 Coxas (posterior pair very 



largely developed for the 

 Figs.! 

 M. Bedel 



8. 



9. 

 10. 

 11. 



14. 

 15. 



support 

 legs). 

 IG. Trochanter. 



17. Femur. 



18. Tibia. 



19. Dilated tarsus, or 



cupules of male. 



20. Oar-shaped tarsus. 



21. Coxal process. 

 Epipleura of elytra 



of the swimminc 



palette, and 



Matthews. 



22. 



23. Genital armature. 



and IV. are from a plate kindly placed at my disposal by 



Figs. II. and III. have been drawn for me by the Rev. A. 



The corneous plates on the segments are called the scuta, and are 

 termed respectively the dorsal and abdominal sada. 



II. Larva of Gi/rmus viarinuSy Gyll. 



III. Larva of Halij/lus fnlvus, F. 



IV. Pupa of Sjjhceridium scarahceoides, F. 



1. Cephalic region. 



2. Thoracic region. 



3. Abdominal region, e. cerci. 



4. One of the " styli motorii." 



Fig. V. Under skeleton of Cychrus. 1. Epimeron of mesothorax. 

 2. Ante-coxal piece (see p. 1). 3. Episternum of metathorax. 4. 

 Anterior coxa. 



Fig. VI. Under skeleton of Pferostichus (numbered as preceding). 



Fig. VII. ,, ,, Mormolyce „ ,, 



Fig. A'^III. „ „ Dytiscus. 1. Epimeron of mesothorax. 



2. Metasternum, showing absence of ante-coxal piece. 3. Episternum 

 of metathorax. 4. Anterior coxa. 



Fig. IX. Under skeleton of Haliplus showing the broad plates that 

 cover a great portion of the abdomen : the parts indicated by dotted 

 lines are covered and concealed by the plates : 1. Ante-coxal piece. 

 2. Abdominal plates. 3. Anterior coxa. 



Fig. X. Under skeleton of Pelobms (numbered as Figs. 5, 6, 7). 



Figures I., If., and III. are after Schiodte, the rest after Horn. 



