256 HABITATIONS OF INSECTS. 



stopped, some in the leaves, other in the twigs, and had there hatched 

 and produced palls ! Redi's solution of the difficulty was even more ex- 

 traordinary. This philosopher, who had so triumphantly combated the 

 absurdities of spontaneous generation, fell himself into greater. Not 

 having been able to witness the deposition of eggs by the parent flies in 

 the plants that produce galls, he took it for granted that the grubs which 

 he found within them could not spring from eggs : and he was equally 

 unwilling to admit their origin from spontaneous generation, — an ad- 

 mission which would have been fatal to his own most brilliant discoveries. 

 He therefore cut the knot, by supposing that to the same vegetative soul 

 by which fruits and plants are produced is committed the charge of 

 creating the iarvEe found in galls ! ^ An instance truly humiliating how 

 little we can infer, from a man's just ideas on one point, that he will not 

 be guilty of the most pitiable absurdity on another ! 



Though by far the greater part of the vegetable excrescences termed 

 galls are caused by insects of the genus Cijnips, they do not always ori- 

 ginate from this tribe. Some are produced by weevils of different genera 

 and species. Thus those on the roots of kedlock {Sinapis arvensis) I 

 have ascertained to be inhabited by the larvae of Nedyus contractus and 

 assimilh. From tlie knob-like galls on turnips, called in some places the 

 amhury, I have bred another of these weevils [Curcullo pleurostigma Marsh., 

 Rynchcenus sitlcicollk (tvII.) and I have little doubt thiit the same insects, 

 or species allied to them, cause the clubbing of the roots of cabbages,^ It 

 seems to be a beetle of the same family that is figured by Reaumur^ as 

 causing the galls on the leaves of the lime-tree. Mr. Westwood has 

 traced the transformations of a minute species oi Balaninus, which resides 

 in the large and fleshy galls on the leaves of willows, occasionally in com- 

 pany with the larvae of Nematus intcrcus; Bouche has also described the 

 larva of Balaninus salicivorus Schon., which is found in the galls on the 

 leaves of Salix vitellina, and that of Gymncetron villosulus, which lives in a 

 gall formed on Veronica beccahunga. According to Hammerschmidt Cleopus 

 ajpnis also resides in galls upon tiie roots of Sinapis arvensis, Clconus Li- 

 7iarice in galls at the roots of Aniirrhinum Linarice, and B/iris ccEridcscens in 

 the stems of Reseda lutea, all in their larva state ^; and Mr, Perris has 

 obtained an Apion {A. ulicicola P.) from galls on the young branches of 

 Ulex namis^, an interesting fact, as proving, with a similar one observed 

 by Mr. Westwood as to Apion Radiolum which he found undergoing its 

 transformations in the stems of the hollyhock®, that all the species of this 

 genus do not pass their larva state in the interior of seeds as most of them 

 do. Other galls owe their origin to moths as those resembling a nutmeg 



1 De Iiisectis, 233, &c. 



2 Mr, Westwood informs us that he has not detected any other larvae in the clubs 

 at the roots of cabbages than those of a species of Mtiscidcz (^Antlwmyia brassicce), 

 and which had evidently been produced from eggs laid in crevices of the already 

 formed clubs. 



3 Keaum. iii. t. 38. f 2, 3. 



■* Bouche NaturgescJi, &c. and Hammerschmidt Observ. Physiol. Pathol, de Plant. 

 Gallaruin Ortu, quoted in Westwood's 3Iodern Classif. i. 342. I have some sus- 

 picion tliat a little weevil, Leiosoma ovatula, of which 1 found ten or twelve early in 

 the spring of 1842, near Bristol, under the leaves of Ranunculus bulbosns, which they 

 had pierced with numerous holes, may reside in the larva state in galls on the root 

 of this plant. 



^ Attn. Soc. Ent. de France, ix. 90. 6 Westwood, ubi supra, i. 837, 



