HYMENOPTERA 37 
Adults in this order are characterized by the possession of two 
pairs of wings, both pairs membranous, the front pair larger than 
the hind pair. The mouth parts are com- 
plex, and are adapted for biting and for 
sucking. However, the structure of the 
mouth parts is not usually of direct eco- 
nonue importance, since the adults do not 
habitually feed on or destroy that which is 
of value to man. 
In one subgroup of the Hymenoptera the 
abdomen of the adult is broad at the 
point where it Joins the thorax; in other 
words, the insects are ‘broad waisted.” 
This section includes the Tenthredinids or pig. 37.— The saws of a 
sawflies, a family containing many injurious — sawfly. Enlarged and nat- 
species. The name sawfly is given to this ees 
family beeause the end of the abdomen in the adult female is provided 
with genuine saws, which it uses in making a place for the deposition 
of its eggs. Sawfly larvee strongly resemble the larve of the Lepi- 
doptera, but may be distinguished from them by the number of pro- 
legs — the false legs situated behind the three pairs of genuine legs 
near the front end of the body. The larve of sawflies usually have 
six to eight pairs of these pro- 
legs, while those of the butterflies 
or moths have never more than 
five pairs. Examples of injurious 
sawflies are seen in the pear slug 
and the currant worm. 
A closely related subgroup of 
| the Hymenoptera comprises a 
number of families in which the 
Fig. 38.—An ichneumon, Prmplt,  fomale ig provided with a boring 
Original. 
apparatus at the hind end of the 
abdomen. These families include some of our important beneficial 
species living as parasites in the bodies of other insects, the Ichneu- 
