HABITATIONS OF INSECTS. 



385 



appearance is communicated to the flowers of Teucrium su- 

 pinum hy a little field-bug, Tingis Teucrii of Host ^, and to 

 another plant of the same genus by one of the same tribe de- 

 scribed by Reaumur.^ In these two last instances, however, 

 the habitations do not seem strictly entitled to the appellation 

 of galls, as they originate not from the egg, but from the 

 larva, which, in the operation of extracting the sap, in some 

 way imparts a morbid action to the juices, causing the flower 

 to expand unnaturally ; and the same remark is applicable to 

 the gall-like swellings formed by many Aphides, as A. Pis- 

 tacicBf which causes the leaves of diflerent species of Pistacia 

 to expand into red finger-like cavities; A. Abietis, which 

 converts the buds or young shoots of the fir into a very beau- 

 tiful gall, somewhat resembling a fir-cone, or a pine-apple in 

 miniature ; and A. Bursarice, which with its brood inhabits 

 angular utriculi on the leaf-stalk of the black poplar, numbers 

 of which I have observed on those trees by the road-side from 

 Hull to Cottingham. The majority of galls are what ento- 

 mologists have denominated monothalamous, or consisting of 

 only one chamber or cell ; but some are polythalamous, or 

 consisting of several. 



Among the more remarkable galls are those so much re 

 sembling minute fungi as to have been actually described as 

 such ; as Sclerotium fasciculatum Schumacher, which is a com 

 mon gall on oak leaves ; and the Rev. M. J. Berkeley has 

 given an account of a similar one found by W. S. MacLeay, 

 Esq., in Cuba, on the leaf of a plant of the order Ochnacece, 

 which on a cursory examination was regarded by some of our 

 first botanists as an epiphytous fungus, but proved on dissec- 

 tion to be a true gall, and distinguished from all previously 

 known by its very curious operculum or lid, evidently meant 

 for the more ready egress of the occupant (which has not yet 

 been ascertained) in its perfect state.^ 



Having thus described the most remarkable of the habita- 

 tions constructed l)y the parent insects for the accommodation 

 of their future young, I proceed to the second kind mentioned ; 



1 Jacquin Collect, ii. 255. 2 Reaum. iii. 427. 



^ Trans. Linn. Soc. xviii. 576. 



VOL. I, C C 



