318 INSECTS AT HOME. 



that they are its lawful inhabitants ; for there are certain 

 iclmeumon flies (of which we shall presently treat) which are 

 parasitic upon the gall insects, and take their place within the 

 galls. 



Some of the habitations produced by these insects are very 

 beautiful. For example, the leaf-galls of the oak are of a 

 pearly translucency, and coloured with golden yellow, orange, 

 and red, like a ripe apple. The currant galls, which hang in 

 strings from the twigs, are similarly beautiful in colouring, 

 while the rich crimson bedeguar of the rose, with its thick, 

 fur-like clothing, is too familiar to need description. 



To secure the insects which inhabit these galls is easy 

 enoup'h. Those which are found at the middle or end of 

 autumn may be plucked, together with the part of the tree 

 to which they are attached, and placed in boxes, each box 

 being carefully labelled with the date and locality of the 

 capture. But when the galls are found at the beginning of 

 summer, this plan often fails, because the galls are still draw- 

 ing nourishment from the sap, and, unless they can do so, the 

 insect does not obtain sufficient nutriment, and either perishes 

 before it can make its way through the partly dried walls of 

 its habitation, or is itself withered, shrivelled, or deformed, in 

 consequence of the deterioration of its food. 



In such cases, the best plan is to take a piece of green 

 muslin or leno, and tie it loosely over the gall. In gardens or 

 private grounds this is always the best plan, and, even in 

 places open to the public, the green muslin will mostly escape 

 observation. Indeed, it is often so difficult to discover, that 

 the safest plan is to note in the pocket-book the particular 

 tree and branch on which any galls have been thus secured. 

 It is rather curious that, although the Gall-flies can gnaw their 

 way through the walls of their former habitations, they seldom, 

 if ever, try to break through the gauze in a similar manner, 

 but crawl about in an uncertain way, as if bewildered with 

 their new position. 



There is one small but remarkable family of these insects, 

 called the Evaniidse, in which the relation, size, and position 

 of the abdomen and thorax are most curiously modified. Like 

 several other groups of insects now inhabiting Britain, thej' 



