CHAPTER XIV. 



WORKERS IN PLANT TISSUES. 



THERE are a large number of insects who are 

 more or less expert workers in plant tissues, 

 using these as shelters either for themselves or for 

 their offspring. As we have already seen, many Wasps 

 work up fragments of woody tissues into the most 

 beautiful papery material with which to build their 

 nests, while the Carpenter Bee excavates galleries 

 in the stems and branches of trees and shrubs, and 

 forms therein a series of partitioned chambers, snug, 

 well-provisioned nurseries for the safe rearing of its 

 offspring. It is to some distant relations of these 

 hymenopterous insects that I would now draw your 

 attention to those sftiall insects which are only known 

 to most people by the results of their labours, for the 

 majority are small enough to escape attention namely, 

 the Gall-flies, scientifically known as the Cynipidce. 



The Gall-flies are responsible for those many shaped 

 and often brightly coloured swellings on leaves and 

 twigs of various trees and plants called galls. The 

 insects are small, frequently minute in size, and usually 

 black or blackish brown in colour. The true nature 

 and origin of the excrescences caused by these flies 

 was a great puzzle to the ancients, and indeed, although 



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