462 Saw-flies, Gall-flies, Ichneumons, 



the egg is deposited, so that the larva on hatching will find it ready to hand. 

 With the social wasps and bees and all the ants, the workers bring food to 

 the larva during its whole life. With the lower forms, the parasitic and 

 gall-making kinds, the egg is deposited on or in a special and sufficient food- 

 supply. All these unusual conditions are described in the discussion of 

 the various groups. Indeed this whole chapter on the Hymenoptera is writ- 

 ten especially with the aim of illustrating the biology, the special life con- 

 ditions and relations of the various larger groups of these insects, rather 

 than with the aim which determined the character of the chapters on the 

 beetles (Coleoptera) and moths and butterflies (Lepidoptera), namely, that 

 of presenting a systematic survey of the classification and individual habits 

 of those members of the order most likely to be seen or captured by the col- 

 lector. The beetles and the moths and the butterflies are the insects which 

 fill the cabinets of the amateur and beginning student, and names and facts 

 concerning particular species are likely to be the particular desiderata in 

 connection with them. But it is the extraordinary and "wonderful" char- 

 acter of the ecological relations and physiological adaptations of the Hymen- 

 optera which make these insects of such interest to nature-lovers, and which, 

 indeed, is the subject that can most profitably be given special attention 

 by any student of the order. Without, therefore, making any further attempt 

 to formulate generalizations concerning this great complex of variously 

 mannered insects, we may begin our study of its members arranged in sub- 

 ordinate groups, this grouping depending rather upon general biologic char- 

 acteristics than strictly classific ones. 



The classification of the Hymenoptera is a matter that interests but few 

 amateurs; only a few families are at all well represented in general collec- 

 tions. Distinction among the more familiar larger groups, as the ants, bees, 

 wasps, saw-flies, horn-tails, and ichneumons, is usually pretty well marked 

 in the general habitus or tout ensemble of appearance. Certain other of the 

 larger groups, composed of minute parasitic species, are almost unknown 

 to the general collector; indeed but two or three American professional 

 entomologists would attempt to distinguish species in these groups. In the 

 following table, therefore, and in the later discussion of the various groups, 

 I have lumped these little-known families together on a basis of common- 

 ness of habit, namely, of parasitic life, and devoted the space to a general 

 account of the extraordinary life-history and habits which these parasitic 

 Hymenoptera have adopted, with some reference to the special habits of 

 certain particular species. Their classification into smaller groups is left 

 undiscussed. 



