EESULTS OF CROSSING TWO HEMIPTEROUS SPECIES. 



489 



Photo 5. Intromittent organs of the five E. servus that were caged daring the winter of 

 1911-12 with three E. variolarius females, one of which was used for our 

 cross-breeding experiments. (The last three of these five males are shown 

 in photo 5, plate 28.) Lengths of the intromittent organs : — 1st (upper), 

 161 mm. 2nd, 162 mm. 3rd, 166 mm. 4th, 146 mm. 5th, 169 mm. 



Photo 6. Intromittent organs from two E. variolarius. These males were raised from the 

 same deposition of eggs from which we raised the females for our cross- 

 breeding experiments. Only one Of these males (the 2nd) is shown in photo 5, 

 plate 28. Lengths of the intromittent organs:— 1st (upper), 104 mm. 2nd, 

 94 mm. 



Photo 7. Intromittent organs from the two F, hybrids of photo 7, plate 28. Lengths of 

 the intromittent organs : — 1st (upper), 126 mm. 2nd, 124 mm. 



Photo 8. Intromittent organs from the two Fi hybrids of photo 8, plate 28. Lengths of 

 the intromittent organs:— 1st (upper), 126 mm. 2nd, 124 mm. 



Photo 9. Intromittent organ from the one Fi hybrid that was preserved as a pinned 

 specimen. This is the only intromittent organ that cannot be compared with 

 a photograph of the insect from which it was dissected. The intromittent 

 organ of the insect of photo 9, plate 28, was broken in dissection, and we 

 therefore replaced it witli this organ from tlie dried specimen. Length, 

 126 mm. 



Photo 10. Intromittent organ oftheFi hybrid of photo 10, plate 28. Length of intro- 

 mittent organ, 109 mm. (This includes 3 mm. for the extreme distal end that 

 was broken off in dissection and not preserved.) This hybrid is the male 

 parent of the r2 hybrids of plate 31. 



Photo 11. Intromittent organ of the Fi hybrid of photo 11, plate 28. Length of 

 intromittent organ, 134 mm. 



This hybrid is the male parent of the F^ hybrids of photos 15 and 16, 

 plate 28. 



Photo 12. Intromittent organ of the Fi hybrid of photo 12, plate 28. Length of intro- 

 mittent organ, 132 mm. 



This hybrid is the male parent of the F2 hybrids of photos 42 to 48, 

 plate 32. 



Photo 13. Intromittent organ of the Fi hybrid of photo 13, plate 28. Length of 

 intromittent organ, 122 mm. 



This male fertilized the two F^ females of the 6th and 7th pairs of F^ 

 hybrids, and is therefore the male parent of the F2 hybrids of photos 49 

 to 57, plates 32 & 33. 



Photo 14. Intromittent organ of the Fi hybrid of photo 14, plate 28. Length of 

 intromittent organ, 126 mm. 



This hybrid is the male parent of the Fo hybrids of photos 26 to 32, 

 plate 30. 



Photos 15 & 16. Intromittent organs from the four Fo males from the fifth pair of Fi 

 hybrids. 

 Photo 15. Intromittent organs of the three F2 hybrids of photo 15, plate 28. 

 Length of intromittent organs : — 1st (upper), 108 mm. 2nd, 107| mm. 

 3rd, 147 mm. 

 Photo 16. Intromittent organ of the Fo hybrid of photo 16, plate 28. Length 

 of intromittent organ, 135 mm. (See photo 11 for the intromittent organ 

 of the male parent of the four F2 hybrids of photos 15 and 16.) 



LINN. JOURN. — ZOOLOGY, VOL. XXXII. 



39 



