New Yoke Agricultural Experiment Station. 323 



These nymphs are the first to cause marked injuries, which is undoubt- 

 edly due to the increased size and the rather sedentary habits of the 

 insects. 



With the fourth instar the wing pads become more noticeable and 

 the insects are of a much greater size. The color remains the same 

 except that the margins of the thorax may be of a pale yellow tinge. 

 The nymph is even less active than before and remains quiet unless 

 suddenly jarred, when it quickly seeks a hiding place. The fourth 

 instar was completed in the breeding cages in either 5 or 6 days. 

 These nymphs were numerous in the pear orchards on June 8, 1912. 

 . The fifth or last instar is completed in 6 days. The nymphs are 

 large and the wing pads are considerably lengthened and have a 

 dark brownish tinge. Individuals of this form were taken from 

 pear trees on June 15, 1909. On June 8, 1912, nymphs of the fourth 

 stage were collected, which molted on the following day and the 

 fifth instar lasted until June 14. 



The adult insects during the years of 1910-1912 appeared between 

 June 6 and June 18. The adults remain on the trees amongst the 

 succulent growth and on the pear fruits for a short time after emer- 

 gence and then disappear. In the laboratory the mature insects 

 lived on succulent tips of pears and fruits for about four weeks before 

 they succumbed. In cages on bearing pear trees they lived as 

 long as three weeks. The adults disappear by the middle of July 

 and during the years of our study of this pest they have not been 

 seen again in the orchards until the following season at the conclusion 

 of the nymphal period. 



HABITS. 



The newly hatched nymphs are frail but very agile creatures. 

 They at first seek the tender, unfolding leaves which they may punc- 

 ture severely, and during periods of rest they may be found in the 

 axils of the leaves or in the folds of leaves which are unrolling. When 

 disturbed they quickly run to places of hiding. With the setting of 

 the fruit they then direct their attacks upon the young pears. Espe- 

 cially attractive to them are clusters of fruits which are growing close 

 together and have not reached such size that their weight pulls them 

 apart. In these the insects find concealed positions and do much 

 damage. On separating the fruits one may find half a dozen or 

 more nymphs, while all of the young pears may be more or less 



