550 SUMMAKY OF CURRENT RESEARCHES RELATING TO 



is in intimate association with it, and knows it as hers. 3. In the 

 next stage the sting is not used for paralysing, only for defence. The 

 booty is killed, made into pap, and laid beside the larva, the mother 

 reserving a tithe for herself. Associated with this is a change in the 

 mouth-parts of the larva, the masticatory apparatus being reduced and 

 a sort of buccal funnel being formed. There is also supra-salivation, 

 and the mother licks the secretion greedily. 4. The next step is a 

 prolongation of the reproductive period and the simultaneous nurture 

 of several larvre. This means that more food is required, but it also 

 means that there is more salivary secretion. What Roubaud calls an 

 " cecotrophobiosis " is established, a nutritive exchange between larvEe 

 and mother. The regime is arranged so that there is a succession of 

 young larva?, for only the young stages produce the attractive secretion. 

 In warm countries the nest is kept up all the year round. 



It seems likely that the social life of wasps arose, not by grouping, 

 but by filial association, and many gradations are known. When young 

 females emerge from the cocoons while the mother is continuing her 

 maternal labours, there is an inducement for them to remain as her 

 collaborateurs if there is abundant stoied food available and plenty of 

 salivary secretion on the part of young larvte. 



In the genus Belonof/asfer the queen may revert to a solitary regime 

 in hard times. When conditions are better, but still not very good, her 

 daughters may be insufficiently fed, and may almost become " workers." 

 They are fertilized, but they are slow to lay. When conditions are 

 thoroughly prosperous there are several functional females in the 

 community. These polygynous nests are found only in warm countries, 

 where nidification goes on without interruption. It is probable that 

 the monogynous nest, with a single queen and with many workers more 

 or less completely sterile, arose in Northern countries and in later times. 

 Social wasps date from the OHgocene and Miocene. 



Social evolution seems to have proceeded along two divergent lines 

 among Hymenoptera. The one line is predatory, with its climax in the 

 social wasps, with Eumenids and Pompilids remaining solitary. The 

 Masaridfe, which do not paralyse booty and are vegetarian (eating 

 nectar, &c.), both as adults and larvte belong anatomically to the 

 Yespiformia. The honey-storing regime finds its climax in hive-bees, 

 with many solitary types and intermediate grades. The solitary 

 Digger-wasps, like Sphex, which paralyse the booty that they store for 

 their young, belong anatomically to the bee-line (Sphegiformia). It is 

 probable that the melliferous regime is derived from the predatory, and 

 that it arose in types where poison was not suitable for the preservation 

 of flesh. 



Agaoninge.* — Gr. Grandi gives an account of a collection of these 

 Chalcidid Hymenoptera made by Silvestri in E. Africa. They are 

 parasites of figs. Nineteen new species of BJastophaga, Ceratosolen, 

 Sijcopliaga., Apocrypta, and other genera are described, and some of 

 them are very strilnng forms, e.g. AUoiriozoon prodigiosiim g. et sp, n. 



* BoU. Lab. Zool. Scuola Agric. Portici, x. (1916) pp. 121-286 (52 figs.). 



