254 NATURAL HISTORY. [cH. XVIU. 



CHAPTER XVIII. 



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NATURAL HISTORY OF PARASITICAL INSECTS FOUND ON 

 PLANTS, AND PARASITICAL PLANTS FOUND ON INSECTS. 



History of the Gall found on the Brambles — Its parasite — History 

 of the Cimex which attacks Flowers — History of a Beetle which 

 attacks Leaves — History of the Caterpillar peculiar for forming 

 Galls — History of the Insect which forms resinous Galls on the 

 Pine-tree — An account of the Fungus found attached to the Mel- 

 olontha or May Bug — An account of the Vegetating Wasp — An 

 account of the Plant found on the Pupa of a Cicada, on Moths, 

 and on Larvae — The sxipposed Causes of these Phenomena — An 

 account of portions of Flowers being found attached to Insects. 



In further illustration of the parasitical insects 

 which form the galls, of which we have given a 

 short account in the former volume, we proceed to 

 describe those which are observed on the brambles 

 in the months of July and August, but which be- 

 come more numerous in September, " It is upon," 

 says Reaumur, " the stems and branches that we 

 noticed the galls, which are sometimes nothing else 

 than the stem and branches themselves, equally 

 swollen on all sides for the space of an inch ; be- 

 yond there is a sweUing of the shape of a spindle. 

 This swelling varies in length, and occasionally it is 

 found only upon one side of the stem. The shape 

 of these tubercles varies considerably, but the part 

 thus enlarged is always harder than those which re- 

 tain their natural size. If we cut one of these galls 

 either transversely or longitudinally, more than 

 twenty or thirty larvae, of an amber colour, will be 

 found in each of them. They seem placed in the 

 space left by the detachment of the fibres from each 

 other, and they gnaw all that surrounds them ; the 



