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The University Science Bulletin. 



instars, and using a different method of rearing, better results were 

 obtained. Various host plants were planted in small flower pots, 

 and the insects were confined on these under lamp chimneys. This 

 was an improvement over the first method, although not entirely- 

 satisfactory. By having the living plant a more steady flow of sap 

 could be obtained, so that the insect, once established was able to 

 proceed without interruptions. The chief difficulties to cope with 

 were in getting the very restless first instars settled, and the fact 

 that the plants became stunted and sickly under glass 'chimneys. 

 Wire cages would have been more satisfactory for the rearing of the 

 later nymphal stages, but would have been too open for the first 

 instar. From some fifty-odd groups of experiments, only seven 

 first-instar nymphs were carried through to adults. Other reliable 

 data for the various stages were obtained piecemeal by counting the 

 length of time from molt to molt. The rearings were carried on on 

 a back porch, so that the temperature was practically the same as 

 in the field. 



First-instar nymphs taken in the field remained the following 

 number of days in this stage : 



April 29 to May 5 7 days 



May 2 to May 9 7 days 



May 3 to May 10 7 days 



May 4 to May 14 10 days 



May 6 to May 17 U days 



May 12 to May 17 5 days 



May 12 to May 21 9 days 



May 12 to May 19 7 days 



May 12 to May 20 8 days 



May 12 to May 21 9 days 



May 12 to May 14 2 days 



May 1 1 to May 21 10 days 



This gives a range of from two to thirteen days for the instar. 

 However, these data are not sufficiently accurate, since the nymphs 

 were not obtained directly from the egg, but were picked up pro- 

 miscuously in the field. Some of them appeared to have just 

 hatched. The average time is probably ten or eleven days. 

 Records for the second instar are as follows: 



May 21 to May 27 6 days 



May 25 to June 3 9 days 



May 22 to May 24 2 days 



May 22 to May 27 5 days 



May 22 to May 28 6 days 



May 24 to May 31 7 days 



June 26 to June 30 4 days 



May 17 to May 25 8 days 



May 17 to May 22 5 days 



May 21 to May 27 6 days 



May 19 to May 25 6 days 



May 19 to May 26 7 days 



May 21 to May 29 8 days 



May 14 to May 21 7 days 



These are accurate counts taken from molt to molt. The range 

 is from two to nine days and the average length seems to be six or 

 seven days. 



