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THE BRITISH NATURALIST. 



[April 



VEGETABLE GALLS AND GALL INSECTS. 



BY S. L. MOSLEY, ESQ., F.E.S. 



Read Lancashire and Cheshire Entomological Society, October 10th, 1892. 



It is a matter of some surprise that out of the large number of 

 students of insect life who exist in this country there are not more 

 who pay attention to the subject of Galls. Such students, indeed, 

 may be counted on the ends of one's fingers, though galls are among 

 the most curious and interesting of insect productions. Perhaps it is 

 because the subject seems too much of a mixture, for while the gall 

 maker, in most cases, is certainly an insect, or a near ally, it is by no 

 means clear that the gall itself, apart from the insect, can be studied 

 as an entomological subject. The student, in fact, must become a 

 kind of entomologist-cum-botanist, not always an agreeable mixture 

 at first sight, but which, after a very short struggle usually resolves 

 itself into a wall of mist, easily passed through. It has also been 

 objected that the study of gall insects as a group is too complicated, 

 as gall makers are scattered over several orders of insects, and some 

 are even not insects at all ; the student has thus not only to be an 

 entomologist and botanist at the same time, but he must be prepared 

 to tackle some of the more difficult departments of entomolog)' — 

 Coleoptera, Diptera, Homoptera. Another objection to the study of 

 galls is that many of them are so soft and succulent that they cannot 

 be preserved so as to make agreeable objects for the cabinet, without 

 which the insects themselves would be of very little interest. Then 

 there are difficulties, I admit, in breeding out the flies, for, unless the 

 galls be gathered just at the proper time (and this is not always easy 

 or convenient to do) we may try in vain year after year to rear the 

 inmates. 



Nov/, I hope that what I am saying will not detract from the hope 

 I have of enlisting you into my sympathy. No one can expect to be 

 a collector of galls without being galled by difficulties and disappoint- 

 ments now and then, just as all collectors are. But let us clear the 

 ground as we go along : we will consider these difficulties. First, as 

 to the botanical difficulty — chat the study of galls involves a consider- 

 able knowledge of plant life. I do not think that it does so more than 

 other departments of entomology, for nothing more is needed than to 

 know the names of the plants, and this even is not absolutely 

 necessary. Galls are usually conspicuous, and such that a person 

 not a botanist may be pretty well certain when he sees a gall that it 

 is an addition to, and not essentially a part of the plant on which it 

 grows. Then having secured the gall, and a part of the plant with it, 

 it is usually a very easy matter to find out the name of the plant, 

 which if one is not able to do himself, he has most probably botanical 



