HABITATIONS OF INSECTS. 291 



from eggs, were chiefly at a loss to account for the conveyance of these 

 eggs into the middle of a substance in which they could find no external 

 orifice. They therefore inferred that they were the eggs of insects depo- 

 sited in the earlh, which had been drawn up by the roots of trees along 

 with the sap, and after passing through different vessels had stopped, some 

 in the leaves, others in the twigs, and had there hatched and produced 

 galls ! Redi's solution of the difficulty was even more extraordinary. 

 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 admission 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 larvae 

 found in galls 1^ 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 Cynips, they do not always origi- 

 nate 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 

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

 ambury, I have bred another of these weevils (^Curculio pleurostigma 

 Marsh., Rhynchcenus sulcicoUis Gyll.), and I have little doubt that 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. West- 

 wood has traced the transformations of a minute species of Balaninus, 

 which resides in the large and fleshy galls on the leaves of willows, occa- 

 sionally in company with the larvae oi Nematus intercus ; 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 Gymnostron villos- 

 ulus, which lives in a gall formed on Veronica beccabunga. According to 

 Hammerschmidt, Cleupus affinis also resides in galls upon the roots of 

 Sinapis arvensis, Cleonus Linaria, in galls at the roots of Antirrhinum 

 Linarice, and Baris carulescens in the stems of Reseda lutea, all in their 

 larva state"*; and M. Perris has obtained an Apion {A. ulicicola P.) from galls 

 on the young branches of Ulex nanus^, an interesting fact, as proving, with 

 a similar one observed by Mr. Westwood as to Apion radiolum which he 



' Ve Imectis, 233, ^c. 



* 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 Muscida (Anthnmijia bramca), and which had 

 evidently been produced from eggs laid in crevices of the already formed clubs. 



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



* Bouche Naturgesch, tfec. and Hammerschmidt Observ. Physiol. Pathol, de Plant. Gallarum 

 ortu, quoted in Westwood's Modern Classif. i. 342. I have some suspicion that a little 

 weevil, Leiosoma ovalula, of which I found ten or twelve early in the spring 1842, near 

 Bristol, under the leaves of Ranunculus bulbosus, which they had pierced with numerous 

 holes, may reside in the larva state in galls on the root of this plant. 



* Ann. Soc. Ent. de France, ix, 90. 



