4- 



PLATE XXVIl/. 



CORIXIDjE. 



Fig. 1. Crayfish bearing eggs of the Corixid Rampfiocorixa acumi- 

 7iata. The arrows show the direction of the water current. The writer 

 believes this accounts for the presence of the first eggs of the Corixid on 

 the first abdominal pleurites. 



Fig. 2. Head of male of Ramphocorixa acuminata from above. 



Fig. 3. Head of female of R. acuminata. 



Fig. 4. Pala of male of R. acuminata. 



Fig. 5. Antenna of 5th instar nymph of R. acuminata. 



Fig. 6. Digestive system of a Corixid to show the termination of the 

 malpighian tubules against the rectal pouch. 



Fig. 7. Front leg of male Palmacorixa huenoa found in Beebe lake. 

 It is a much larger bug than is found in Bool's Backwater, nearby. See 

 plate XXIV. 



Fig. 8. Egg of Ramphocorixa acuminata. 



Fig. 9. Front leg of male Palmacorixa gillettei. Abbott. Copied from 

 Abbott. 



Fig. 10. Front leg of Palmacorixa buenoi. Abbott, from Bool's Back- 

 water. 



Fig. 11. Same as figure 10. Note the variation. 



Fig. 12. The hatching of a Corixid. First a bubble appears after the 

 egg bursts, then the nymph slowly fills the bubble. This postnatal molt 

 bursts when the nymph is two-thirds way out. It remains as a cast and 

 crumpled garment as shown. 



Fig. 13. Male pala of Corixid: 



Fig. 14. Eggs of various species of Corixids. 



Fig. 15. Corixid egg. Showing how the egg enlarges as embryo de- 

 velops within. 



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