1919 



ENTOMOLOGICAL SOCIETY. 



85 



The NyMPir. 



Description: 1st instar. Oval and very flat in shape. Antennae translnceni 

 with dusky tips. Eyes reddish. Head pale yellow with a narrow median line of 

 cream. Thorax pale yellow. Abdomen yellowish with luniile of deep orange. 

 Legs translucent, dusky tarsi. Length .36 mm. 



3nd instar. Similar to the 1st. Length .54 mm. 



Similar to the 1st. Wing-pads apparent. Length .72 mm. to 



3rd instar. 

 8 mm. 



4th instar. 

 5th instar. 



Similar to the 5th. Length .9 mm. to 1.08 mm. 



Oval and very flat in shape. Antennae light brown with dark 

 brown tips. Eyes reddish. Head dark brown with a longitudinal median line 

 of creamy grey. Thorax creamy grey blotched with red, with dark brown markings 

 arranged as in illustration; wing-pads dark brown. Abdomen: anterior third 

 creamy grey with three dark brown transverse bands interrupted in the middle, 

 posterior two-thirds dark brown. Length 1.44 to 1.62 mm. (Eig. 18). 



Fig. 18. — "a" Egg; "6" Various stages of 

 psylia nymphs. (Ail muca enlarged.) 



Habits : LTpon liatching out in the spring, the nymphs of the first generation 

 migrate to the opening buds where they feed principally on the leaf petioles and 

 blossom stems. The nymphs of the later generations are found chiefly on the 

 upper and under side of the foliage. They also occur to some extent on the 

 tender wood, especially in the fall. 



The nymphs secrete copious quantities of honeydew, and, as a general rule, 

 are enveloped by this liquid. According to our observations, the nymphs of the 

 first generation secrete less honeydew than those of the succeeding broods. 



Molting: The nymph molts five times, attaining the adult stage after the 

 fifth molt. In experiments with 39 individuals the average duration of each 

 instar was: 1st instar 6 days: 2nd instar 6 days; 3rd instar 6 days; 4th instar 

 ■6 days; 5th instar 8 days. 



Length of Nymphal Life: In experiments conducted with 192 individuals 

 of the 1st generation, the duration of the nymphal stage varied from 20 to 35 davs 

 with an average of 28 days. 



