XU INTEODVCTION. 



Key to the Families of the Diploptera. 



A. Intel-mediate legs armed with one tibial 



ealcar ; claws of tarsi bifid or dentate : species 



solitary Eumenidae. 



B. Intermediate legs armed with two tibial cal- 



caria ; claws of tarsi simple : species social . Vespidae. 



Key to the Families of the Anthophila. 



A. Tongue short, obtuse, emarginate or bitid at 



apex Colletidae. 



B. Tongue short and acute, or long (sometimes 



very long) and acute, never emarginate .... Apidae. 



The arrangement o£ the Hymenoptera in this volume, so far 

 as the primary divisions go, is based on the classification adopted 

 by Dr. D. Sharp in the Cambridge Natural History volume on 

 Peripatus, Myriapods, and Insects. In the divisions of the 

 Aculeate section of the suborder Petiolata I have followed, Avith 

 certain modifications, the arrangement given in Mr. E. Saunders' 

 valuable work on the Hymenoptera Aculeata of the British 

 Islands. With regard to the Anthojihila, I agree with Mr. 

 Saunders that the distinction between the bees with obtuse 

 emarginate tongues and the bees with acute non-emarginate or 

 simple tongues is of greater importance than the distinction 

 between the usually accepted divisions of the tribe, Andrenidce 

 and Apidce. On the other hand, I have preferred to place the 

 whole of the bees with acute tongues under the family Ajndce, as 

 there seems to me no choice between this and dividing them 

 into several families or subfamilies, as proposed by Schraiedeknecht, 

 Dalla Torre, and others. 



The present volume appears under the disadvantage of being 

 the first attempt at describing the Wasps and Bees of India 

 as a whole ; no complete list even has hitherto been published, 

 nor have the Hymenoptera received nearly as much attention 

 from Indian naturalists as the Lepidoptei-a. Whilst, therefore, 

 it may be hoped that this book will direct the attention of ob- 

 servers and collectors in India to a most interesting though 

 somewhat neglected order of insects, and that it will facilitate the 

 identification of the species which occur, it must be remembered 

 that not only is our general knowledge of the Indian Hymeno- 

 ptera very incomplete, but our information as to the distribution 

 of the species hitherto recorded is singularly imperfect. For 

 many of the species described in the following pages no more 

 exact locality is known than " India." Some species to which an 

 Indian origin was erroneously assigned by the older writers are 

 omitted in the present work, and it is probable that a few more 



