384 CLASS VIII. 
palps four- or five-jointed, labial with two or three joints. Thorax 
gibbous, with mesothorax very large. Abdomen compressed. 
Borer extremely slender, with three sete, concealed, rolled spirally, 
between a bivalve sheath, exsertile from the last ventral chan- 
nelled segment of abdomen. 
Gall-wasps. The females of this family pierce different parts of 
plants (leaves, leaf-stalks, buds, &c.) and lay an egg in the wound. 
The irritation thus produced causes the sap to flow in greater abun- 
dance to the wounded part, and thus different excrescences, often of 
very singular kinds, arise, which serve the larva both for food and 
habitation. The form of the excrescences is different for different 
species, and may serve for recognising and distinguishing them. 
The larve, bent into a semicircle, lie as thick white maggots 
in the cavity of these excrescences. Some species undergo their 
metamorphosis in this situation ; others leave it before becoming 
nymphs, and change under ground. It is true that species also of 
Chalcides are found in these excrescences, which were formerly 
placed with species of Cynips in one genus, and to which GEOFFROY 
gave the name of Cynips exclusively, which occasioned much 
confusion in the nomenclature: they are ichneumons which have 
taken the place of the natural inhabitants. 
Gall-wasps, although living upon vegetable food, have neverthe- 
less a great aftinity with the /chnewmonides, and this is shewn more 
distinctly by the fact that some species (Adlotria Westw.) really 
live like ichneumons in insects (Aphides), without on that account 
differing from the rest of the Cynipides by natural characters or 
organisation (Wexstwoop, J/ntrod. to modern Classificat. of Ins. 1. 
p. 132, Rarzesure, Die Yorst-Insecten, 111. p. 54). 
To the excrescences, caused by gall-wasps, belong also the gall- 
nuts or gall-apples, of which those that come from the East (from 
Aleppo) are in most esteem. They consist, besides gallic acid, in 
great measure of tannin, and are consequently very astringent. Hence 
their use in medicine. Their property of forming a black pre- 
cipitate with salts of oxyde of iron, causes these gall-nuts to be 
employed in the preparation of writing-ink. 
Comp. on this family : Maupieuius de Gallis, in Anatomes plantarum 
parte alterd (Operum ed. Londin. 1686, fol. Tomo i. pp. 17—38); 
OLIVIER, Encycl. méth., Hist. nat. des Ins. V. 1790, pp. 772—792, 
BRANDT u. Rarzesure, Medizin. Zoolog. i. s. 144—158; BOYER DE 
FonscotomBe, Description des Ins. de la fam. des Diplolépaires qui se 
