236 AOKICDLTLJRAL ExPKRIMENT STATION, ItHACA, N. Y, 



eral times during the winter; tlie adults remaLnei in their hiding 

 places, and none were seen in copulation, nor were any eggs seen 

 before April 7, 1892. It was thus evident that Psylla pyricola 

 doas not pass the winter in the egg state, but that there is a hiber- 

 nating brood of adult^s whose eggs are not laid until spiing. 



Oviposition of the winter brood. — A few days of wann spring 

 weather occurred about April 7, 1892, and many of the hibernating 

 adults A\ere sc^n in copulation, and a few eggs were also laid. 

 Spring then opened, and by April eighteenth a majority of the 

 eggs had been deposited. The eggs were placed 'in the creases 

 of the bark, or in old leaf sears, about the base of the tenuinal 

 buds of the preceding year's grow^th; some w^ere seen about the 

 side buds near the terminal ones. They were usually laid singly 

 but rows of eight or ten were sometimes found. The eggs (Fig. 4) 

 are scarcely visible to the unaided eye; it w^ould take eighty of 



Figure 4.— Egg. 



them placed end to end to measure sm inch. They are elongate 

 pyriform in shape, smooth and shining, and of a light orange ^-el- 

 low color when fin^ laid, becoming darker before hatchiug. A 

 short stalk on the larger end attaches the egg to the bark, and a 

 long thread-like process projects from the smaller end. 



Tlie tem]R^rature conditions in the spring influence not only 

 the time of oviposition of the winter bi-ood, but also tlie dura- 

 tion of I lie egg stage. Eggs brought into the warm insectary on 

 Ajjril iseventh hatched in eleven days. Other branches containing 

 cuiis were tied to trees near bv, the end of the cut branch being 

 kept in a vial of damp sand; these eggs hatched in seventeen days. 

 The ^^•eather remaining cool, the eggs uinm the trees undor natural 

 conditions did not hatch before May tenth, or more than a montii 

 after oviiiosit'ion began. By May eighteenth, most of the egg-s had 

 hatched; and the hibeiiiating adults had disappeared. 



Habits of the njanph.— Immediately after emerging from the 

 egg, the minute n^niph seeks a suitable feeding place and is 

 soon at work sucking the sap with it® short beak wliich appears 



