446 INTRODUCTION TO ZOOLOGY 



Classijicaiion of. the Hymenoptera mentioned, in Chapter XXVII. 



Sub-order. Hymenoptera parasitica. 

 Family 1. Tenthredinidae (the Saw-flies). 



Genera. Lophyrus pini (the Pine Saw-fly). 

 Hylotoma rosae (the Rose Saw-fly). 

 Nematus ribesii (the Currant Saw-fly). 

 Nematus gallicola (the "Bean Gall" Saw-fly). 

 Athalia spinarum (the Turnip Saw-fly). 

 Family 2. Siricidae. Sirex gigas (the Wood Wasp). 

 Family 3. Cynipidae. The Gall Wasps and Inquilines (for 



Genera see pp. 441, 442). 

 Family 4. Ichneumonidae (the true Ichneumon Wasps). 



Genus. Paniscus. 

 Family 5. Braconidae (the false Ichneumon Wasps). 

 Genus. Microgasier ( — Apanteks). 



Practical Work, on Saw-flies and Gall Wasps 



1. The larvae of one of the larger saw-flies, the Pine Saw-fly or 

 the Turnip Saw-fly, should be searched for, and when found, kept 

 in a glass-covered breeding-box with plenty of its food plant. Its 

 metamorphosis can then be watched. Careful sketches should be 

 made of the diff^erent stages in its life-historj'. 



Other saw-flies which are found may be identified by reference 

 to P. Cameron's Monograph on British Phytophagus ^ Hymenoptera. 



2. A few Marble Galls {Oynips hollari) should be collected in 

 the autumn and kept in a covered glass vivarium until the Gall 

 Wasps emerge, when they should be carefully studied and sketched.^ 

 They should then be placed on an oak twig surrounded by 

 a muslin bag, or better still on an oak sapling grown in a pot, 

 which can be enclosed in a light wooden frame covered with 

 muslin over the sides and with glass at the top. The insect may 

 then be seen piercing the base of a bud and laying its eggs there ; 

 the gall will first become apparent in the following May. 



3. Other Oak Galls with a more complicated life-history should 

 also be collected, and the alternation of generations in them 

 carefully followed. For their investigation it is well to have a 

 number of little oak trees, about six years old, in pots, with 

 movable covering-frames as described above, and those gall insects 



' Phytophagus = plant-eating. 



^ Some will emerge in October or November, but others will remain in the 

 gall until the spring. 



