Woodworkers 



here we are up against a problem on which we feel that 

 we are justified in letting ourselves go a little, for the whole 

 subject is of such absorbing interest that we shall prob- 

 ably be forgiven for our lapse. The spangle galls some- 

 what resemble the collections of spores, called sori, to be 

 found on the backs of fern fronds ; they are lens-shaped 

 and hairy ; they vary in colour from pale yellow to deep 

 brown. Towards autumn the oak leaves fall and the 

 spangle galls with them ; in each gall there is a gall 

 insect larva. During late autumn the rains cause the galls 

 to swell and increase in size considerably, but the larva 

 within continues to feed, paying no heed to frost and 

 snow and rain, for it is well protected from the elements. 

 In the spring the insect changes into a chrysalis, and 

 emerges as an adult insect a little later. 



Each and every insect coming from a spangle gall is 

 a female ; no males have ever been discovered. Unless, 

 therefore, Nature came to the rescue, this race of gall 

 insects would soon die out. This is not to be, for these 

 females can reproduce their kind without the help of a 

 male, a feat which is not uncommon in the insect world. 

 The females from the spangle galls are provided with 

 very long ovipositors, and they waste no time in plunging 

 them deep into a dormant oak bud and depositing their 

 eggs on the as yet undeveloped catkins, or sometimes on 

 the leaves. As the bud develops the catkins elongate and 

 are seen to bear one or more round growths about the size 

 of a currant, green at first but ripening later to a bright 

 red colour, thus still more closely resembling the fruits from 

 which they derive their name. About May the adult 

 insects emerge from their galls, and they are both males 

 and females, the latter differing from their sisters of the 

 spangle-gall generation in many respects, notably by the 

 absence of a long ovipositor, which would be useless, 

 seeing that they lay their eggs just below the skin at the 

 back of an oak leaf eggs that are destined to form larvae 

 causing spangle galls. 



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