2 GUIDE TO INSECTS. 



species, and these are still used, but as a matter of convenience only. 

 The common " oak-apple " (39) is a very good example. The males 

 and females that come out of these are called Andricus termmalis. 

 These females deposit their eggs on the roots of the oak, and produce 

 small woody galls. From these root galls comes in the winter a 

 much larger wingless insect, called Biorhiza aptera. These are all 

 females. They crawl up the tree and deposit their eggs in the buds, 

 which in the spring develop into the well-known oak-apples. 



The marble gall (43) is still an enigma. The insects that come 

 from these, Cynips Kollari, are all females. Although this insect 

 is so common, the male has hitherto baffled all efforts to discover it. 



Other galls of Cynipida are one on ground ivy formed by Avlax 

 glechomce (45), and a curious swelling in the stem of bramble formed 

 by Diastrophus nibi (47). 



On the east side of the gallery will be found models relating to 

 Coleoptera (49-59), Hymenoptera (61-71), Lepidoptera (73-85), 

 and Diptera (87). The larvae of a great many Phytophagous 

 beetles live on the under sides of leaves, eating the soft parts. The 

 Mustard beetle, Phcedon cochlearm (49), sometimes attacks cultivated 

 mustard with disastrous consequences, as the larvae eat the flower 

 buds as well as the leaves. Another model of great interest is one 

 showing apple-buds injured by the Apple-blossom weevil, Anthonomus 

 pomorum (53). The remarkable way in which certain weevils cut 

 and roll leaves to form their nests is illustrated by Attelabus (57) on 

 oak, and Rhynchites (59) on birch. The models relating to Hyme- 

 noptera include cherry injured by Slug-worm, Blennocampa cerasi 

 (61 ) ; galls on willow formed by another saw-fly, Nematus gallicola 

 (63) ; a third shows the gregarious habits of Pamphilus flaviventris 

 (45) ; the way in which the Leaf-cutting Bee, Megachile willugh- 

 Uella (71) forms its nest is shown by a single cell separated into 

 pieces. 



All the models relating to Lepidoptera (73-85) will repay study ; 

 perhaps the one that has received the most attention is the oak 

 attacked by Tortrix viridana (77), the trees in the spring often being 

 stripped of their leaves by this insect. 



The British Insects (including the beautiful collection of Cater- 

 pillars of Butterflies and Moths, prepared by the Et. Hon. Lord 

 Walsingham) will be found in cabinets on the west side of the gallery. 



The Foreign Insects are on the east side. 



A large case on the east wall is devoted to a description of the 

 external anatomy of insects. The series is not yet complete. 



