INTRODUCTION. 



On morphological grounds wasps may be divided into two main 

 groups, the Sphecina or digger-wasps, and the Vespina or true 

 wasps, the latter of which have their wings folded in plaits when 

 at rest. (Compare Figs. 1 and 2.) For the purpose of this paper, 

 which is a study on habit, wasps may best be divided into the 

 social and the solitary. This classification, based on habit, does 

 not coincide with that based on the condition of the wings, for 

 while the Sphecina are all solitary, the Vespina also include a large 

 group of solitary wasps, the Euraenidae. 



To render my account more complete, I shall briefly compare 

 the habits of the social and the solitary wasps, transcribing from 

 others. 



A social community includes three castes : queens, drones, and 

 workers. The queens alone survive the winter after mating with 

 the drones, which, with the workers, perish of hunger and cold. 

 In the spring the queen builds the first comb and rears the first 

 lot of workers. These immediately take up the work of building 

 the nest and feeding the young, while the queen devotes herself 

 exclusively to egg-laying. Before long, many hundreds of workers 

 are busy in the nest, and, late in the season, many queens and 

 drones also appear, and the cycle of life is started anew. 



The solitary wasps have only two sexes, the queens and the 

 drones, and there is no division of labor, though some genera 

 (Pelopaeus, Bembex and Microbembex) build their individual nests 

 close together, forming colonies. There is a great diversity of 

 habits both among the Eumenidse and the Sphecina. In either 

 group the nests may be made of mud and attached, for shelter, 

 under rocks, the eaves of buildings, or the hollows of trees, or 

 they may be attached to the stems of plants. The nest may be 

 tubes in the stems of plants, in boards • or in the ground, either 

 found ready made, or, as is usual, newly bored or dug by the 

 individual wasps using them. 



The adult wasps live on the nectar of flowers or on animal food, 

 namely the same insect prey which they give their offspring. This 

 usually consists in a given species of wasps of a particular kind 

 of insect, one capturing only caterpillars, others only spiders, flies, 

 bugs, beetles or other insects as the case may be. 



