231 E. P. Stebbing — Life-History of Cherines abietis-piceae Steb. [No. 4, 



absent. The eggs so laid hatch within a week of being laid, and the 

 young larvae spread out over the undersurfaces of the still young green 

 needles and remain feeding on them. At times these undersurfaces are 

 quite black with the numbers of dark crimson-coloured larvae attached 

 to them. The production of these apterous forms continues until the first 

 week in July, i.e., up to the period when the monsoon rains burst over 

 the Himalayas. 



Towards the end of May, however, or beginning of June, the apterous 

 crimson larvae collect at the base of the needles and on the needle-bear- 

 ing shoots. The irritation set up by their sucking operations causes the 

 needles to draw together into a kind of corkscrew-shaped bud, the needles 

 being twisted round one another and stuck together by the sugary excre- 

 tion from the aphids. This excretion is also added to by an exuda- 

 tion of turpentine from the plant and round nodules of resin are to be 

 found in the axils of the needles. A new and larger form of larvae now 

 begins to appear, yellowish in colour. These yellow aphids are to be found 

 in the axil at the base of each needle, each having its proboscis firmly 

 fixed in the tiss ue of the stem or leaf base. In addition to these yellow 

 apterous forms a winged generation began to appear on the trees at the 

 beginning of June. The winged insects found at this stage were on the 

 twisted-up silver fir needles. 



Apterous yellow larva. — Bright canary yellow with two curled, 

 white, cottony, whisp-like tails at the posterior extremity of its body. 

 Patches of the white cottony material are also present elsewhere on 

 body. The proboscis is short ; antennae six-jointed. 



Winged form. — Dark orange-yellow in colour. Four wings large and 

 black. 



The crimson-coloured larvae in the cotton developed stage of their 

 existence are also numerous within the corkscrew-twisted needles. 



The action of the insects at this stage is to contort and dwarf 

 all the new shoots attacked. Some young trees were found with 90 °/ of 

 the new leaves treated in this way, whilst the branches below and the 

 stem shewed numerous patches of eggs covered by the white cottony 

 substance. 



A few days later I was able to note that the yellow larvae are also 

 to be found in the open on needles which are not twisted-up in the 

 corkscrew manner. Later on I found a winged form of the apterous 

 yellow larva. 



Winged form of apterous yellow larva — Yellow green, with Light 

 silvery wings, one and three-quarters to twice the length of body ; pro- 

 boscis yellow as are the legs. 



Observations were continued up to the first week in July upon these 



