HYMENOPTERA. 
Two pairs of wings of almost equal size, hyaline and with few veins. The 
antennas simple, straight or elbowed. The mouthparts mandibulate, 
the labium and maxillae formed in some cases into a lapping tongue. 
The thorax complex, the parts accurately co-adapted to form a rigid 
whole. An extrusible ovipositor is present. Metamorphosis complex, 
the larva freeliving or, more usually, dependent for food on a host or 
on the parent and in this case a white apodousgrub. In both the latt er 
the imaginal life is the active period, usually of long duration The 
order includes herbivorous insects, feeding in or on plants, parasites 
in insects, stinging predators feeding their young on paralysed insects 
and spiders, and social or solitary insects deriving their food from 
flowers, from waste matter (scavengers) or from living insects. 
The sawflies, gallflies, ichneumons, cuckoo-wasps, bees, ants and 
wasps which make up this order are readily recognised in the field: the 
order is a very large one, with a great number of known species, and 
perhaps a greater number of undescribed species than any order except 
Diptera. It includes insects of the very highest importance to agricul¬ 
ture, and some of great economic value but few that are destructive to 
crops or merchandise. 
The classification of this large order is simple, and though authors do 
not agree as to the details, the broad lines are generally accepted. Ash- 
mead has revised the whole classification and introduced a new nomen¬ 
clature, but, while this is accepted in America, it is not that accepted in 
Europe and differs from that still adhered to in England. We must here 
follow the Fauna of India. The order is divided into Sessiliventres, with 
the abdomen broadly attached to the thorax, and Petiolata with the 
abdomen connected to the thorax by a petiole. The Sessiliventres in¬ 
clude only three families of phytophagous insects, which are borers in 
plants or feed on leaves. The Petiolati includes the remaining 24 
families, which fall into three series :—The Parasitica , with divided 
trochanter and extruded ovipositor, the Tubulifera and Aculeata with 
HT 11 
