760 



THE NATURE BOOK 



cells is entirely' concealed under a dense 

 growth of long, many-branched fibres, 

 which possibly represent the abortive 

 attempts of the irritated meristem tissue 

 to develop into leaves. In colour, these 

 fibres are green, pinkish or crimson, and 

 the whole gall is a very pretty object. 



the two unicellular galls fall to the ground, 

 whereas the big " bedeguar " remains 

 on the bush throughout the winter. The 

 grubs pupate within the galls, and the 

 perfect flies emerge the following year, to 

 perpetuate their species (and the respec- 

 ti\"e gall formations) in a perfectly straight- 

 forward manner, and 

 (3 without the interven- 

 tion of a perplexing 

 agamic generation. 



The Gall-fly which, 

 in many respects, is at 

 once the most curious 

 and the most interest- 

 ing of all the species 

 found in England, is 

 the insect which comes 

 from the well-known 

 "Marble Gall," often 

 produced in such num- 

 bers upon young oaks, 

 or upon the shoots of 

 pollarded oaks in 

 hedgerows. Cynips 



"MARBLE GALLS," FORMED BY CYMPS KOLLARI. 



The next of these rose-bush galls is 

 that formed by the fly called Rhodites 

 eglanteria. It is about the size of a 

 pea, greenish ripening to crimson as to 

 colour, and must be looked for upon the 

 under side of the leaves. Each of these 

 galls has onh' one tenant, except in rare 

 cases where marked distortion suggests 

 that two or more galls have coalesced 

 on account of their juxtaposition upon 

 the leaf. The third gall is formed by 

 Rhodites nervosus, and is also found upon 

 the under side of the leaf. But it is per- 

 fectly distinct from the kind just 

 mentioned on account of the thorn-like 

 projections which S})ring from its surface, 

 like the spikes on a medirex'al war club. 

 Almost any hedgerow in England will 

 supply specimens of these three galls, 

 so that the reader may readily compare 

 them, and breed from them their 

 respective tenants. In the case of each 

 species the eggs are laid in the spring or 

 early summer, while the galls reach jx^r- 

 fection alxjut September. In the autumn, 



kollari is the name bestowed by science 

 upon this Gall-fly, in compliment to 

 the old Continental naturalist, V. Kol- 

 lar, who first noticed it. Curiously 

 enough, this insect — which had been 

 well known in Europe for \'ery many 

 vears — was not observed in England until 

 the year 1834 or thereabout. By some 

 means the fly, or its galls, must have 

 been introduced to this country, and so 

 well did the change suit it that, twenty 

 years later, the species was reported as 

 being abundant in the south-western 

 counties, where it had gained the popular 

 name of " Devon gall." To-da\', it may 

 be found in most parts of England and 



