THE PEAR LEAF-WORM. Fi 
subjected to a large amount of heat and desiccation. Thus it is 
evident that the larva and its cocoon must be able to withstand 
considerabie dryness. An experiment was performed at Wenatchee, 
‘ Wash., to learn whether moisture was necessary to the larva. 
Cocoons were collected from the soil within a few days after they were 
spun, in May, 1914, and divided into two lots, both of which were 
kept on the surface of some soil in jelly glasses. The soil in one lot 
was kept moist by pouring water through a glass tube inserted in the 
soil. The other lot was allowed to remain dry. The first lot was 
kept moist until September. After this both lots were left untouched 
until spring, being kept over winter in an unheated room. During 
the emerging period the first lot was again kept moist, while the 
other remained dry as before. As a check on these lots the emergence 
from a third lot, collected April 3, 1915, was recorded. Table I 
gives the results of this experiment: 
TABLE I.—Adulét emergence of pear leaf-worm from moist and dry cocoons, Wenatchee, 
Wash., April, 1915. 
Cocoons col- 
Observation. Moist. | Dry. | lected Apr.| Total. 
, 1915. 
: ES | ee ese 
IN[(oban] ove12 Oi Corgowukhe se 44 ssa sdes ot ospbscsoqeceedsau Sodan aeeeens 59 194 55 308 
IN[ubaaloyere GiadeANOl sh dis So oseoeseb odo eee oodSodbobob ojo onSceSSoondoOe 51 118 31 200 
IEE) a CIOS VON FC ee OBE Soe EME SABES ojo QomsbeE hoo sSoos sbSdcoosbaes 86.4 60.8 56. 4 64.9 
From Table I we learn that 86.4 per cent emerged from cocoons 
kept moist during the previous summer, 60.8 per cent from dry co- 
coons, and 56.4 per cent from the cocoons collected April 3, 1915, and 
which were thus under natural conditions during practically the whole 
period; the total percentage emerging was 64.9. The cocoons of the 
dry lot that did not give adults were examined later, and a number 
of them contained fully-formed adults that had been unable to break 
through the tough, dry cocoon. This indicates that the smaller per- 
centage of adults emerging from these cocoons was due to the dryness 
at the time of emergence rather than the dryness during the preced- 
ing summer, and perhaps collective dryness weakened the insects 
somewhat. The larve had lived through the dry period of the sum- 
mer, had pupated the following spring, and the adults had cast the 
pupal skin, but had been unable to get through the dry cocoon. 
The smaller emergence from cocoons collected in April, 1915, is 
explained by the more uneven conditions to which thev had been 
subjected, such as the freezing and thawing of winter. 
The newly-molted pupa is entirely pale green, with black eyes, and 
measures about 5mm. by 1.7 mm. Shortly before the time for the 
adult to emerge the pupa turns dusky blackish, with the wings, fore- 
legs, and portions of middle and hind legs yellowish. Ventrally the 
abdominal rings and the saw case of the female are greenish. 
