PLATE XXIII. 



OVIPOSITOR OF NOTONECTjE. 



This plate contains three views of the left member of the first pair 

 of gonapophyses of the fem.ale of each of the species of the genus Noto- 

 necta available in this country. Two species have been omitted because of 

 the lack of material. 



The views ai-e from left to right, outside or lateral view; ventral view 

 showing the organ on edge, inner view. All of the drawings were made 

 with camera lucida and drawn to the same scale. The length of the adult, 

 together with outside measurements of the ovipositor, are added for 

 purposes of comparison of relative size of parts. The writer believes that 

 a study of these organs should be taken into account in determining rela- 

 tionship of species. A study of a wide series would certainly establish 

 the range of variability in size and shape of these parts, and in some 

 cases, if not all, aid in specific determinations. The drawings here pre- 

 sented are, however, intended to indicate merely the correlation of this 

 organ with the habit of oviposition. 



Fig. 1. Notonecta lutea. Size of adult, 13-17.1 mm ; valve of ovi- 

 positor, 1.625 mm. x .725 mm. Specimen loaned by Mr. Gibson, of Nat. 

 Mus. Taken in Finland by Sahlberg and determined by Kirkaldy. 



Fig. 2. Notonecta raleighii. Size of adult, 9 mm.; valve of ovipositor, 

 .4 mm. X ,25 mm. Specimen given to me by Mr. J. R. de la Torre Bueno. 



Fig. 3. Notonecta undulata. Size of adult, 10-13 mm.; valve of ovi- 

 positor, .5 mm. X .312 mm. Material from Ithaca, N. Y., and Lawrence, 

 Kan. 



Fig. 4. Notonecta variabilis. Size of adult, 8.2-10.2 mm.; valve of ovi- 

 positor, .4 X .312 mm. 



Fig. 5. Notonecta insulata. Size of adult, 12.6-15.5 mm.; valve of 

 ovipositor, .7 x .425 mm. Material from Palo Alto, Cal. 



Fig. 6. Notonecta glauca. Size of adult, ?; valve of ovipositor, 1.125 

 x .55 mm. Loaned from Nat. Museum by Mr. Gibson ; a specimen from 

 England, collected by Uhler. 



Fig. 7. Notonecta Mexicana. Size of adult, 11-14 mm.; valve of ovi- 

 positor, .7 X .5 mm. Specimens from Arizona. 



Fig 8. Notonecta shooterii. Size of adult, 8-13 mm.; valve of ovi- 

 positor, .65 X .375 mm. Specimen given to me by Mr. J. R. de la Torre 

 Bueno. 



Fig. 9. Notonecta irrorata. Size of adult, 11.8-14.4 mm.; valve of 

 ovipositor, 1.675 x .575 mm. Material taken at Ithaca, N. Y. 



Fig. 10. Notonecta uhleri. Size of adult, 12 mm. ; valve of ovipositor, 

 .65 X .35 mm. Specimen given to me by Mr. de la Torre Bueno. 



Fig. 11. Notonecta indica. Size of adult, 10.5 mm.; valve of oviposi- 

 tor, .5 X .375 mm. Material from Douglas, Ariz., collected by Doctor 

 Snow. Plate first used in Ento. News, XXVI. 



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