PARTHENOGENETIC PURE LINE OF APHIS AVEN.-E FAB. 67 



follows, beginning with the twenty-ninth generation: 1 1:1.257, 

 1:1.278, 1:1.162, 1:1.178, 1:1.320. 



4 In two instances the fraternal means show the antennal lengths 

 to be greater than they were for the first^fraternity obtained. 

 The last fraternal mean obtained, 1:1.320, shows the average 



27 



2? 11 30 31 3i 33 



FIG. 4. FIG. 5. 



FIG. 4. Plotted curve for isolation No. 7. Selections made for increasing the 

 length of the antennae in comparison with the length of the body. The figures in 

 a column to the left refer to the length of body in terms of the antennal length of 

 the same individual taken as unity. Curve plotted on same plan as in previous 

 figures. 



FIG. 5. Results of selections made in isolation No. 8, in the opposite direction 

 from those made in isolation No. 7. Curve plotted on same plan as in Fig. 4. 



length of the antennae in comparison with that of the body to 

 be considerably less than it was in the first fraternity (twenty- 

 ninth generation) obtained, but it was considerably longer than 



1 The length of the antennae is taken as unity as it is always less than the length 

 of the body. 



