332 THE STUDY OF INSECTS 



Bequaert. Since there is lack of agreement regarding the names of 

 genera and families we have preferred to retain the older forms. 



In order for the student to use the keys to advantage certain terms 

 need to be defined. 



The propodcuni. — The first abdominal segment when it forms a 

 part of the alitrunk or wing-bearing region of the body. 



The posterior lobes of the pronotum. — A distinctly differentiated 

 rounded lobe, on each side covering the spiracle, which forms the lateral 

 extension of the pronotum of Sphecoidea. 



The prepectus. — An area along the cephalic margin of the episternum 

 of the mesothorax which in some Hymenoptera is separated by a suture- 

 like furrow. 



The gaster. — The swollen portion of the abdomen behind the pedicel 

 in the suborder Clistogastra. 



The pygtdial area. — In many of the aculeate or stinging Hymen- 

 optera there is an area on the pygidium which is bounded on each side 

 by a carina, the two carinas meeting posteriorly on the middle line of 

 the segment; this area is known as the pygidial area. 



The anal lobe. — The portion of the anal area of the hind wing which 

 is cut off by the axillary excision (Fig. 576). 



The axillary excision. — A notch in the inner margin of the hind wing 

 near its base (Fig. 576). 



ae Pae 



Fig. 576. — Hind wing of Elis showing anal lobe; axillary excision, a; preaxillary excision, pm. 



The preaxillary excision. — A notch in the inner margin of the hind 

 wing distad of the axillary excision (Fig. 576). 



The preanal lobe. — That portion of the anal area of the hind wings 

 that lies between the axillary excision and the preaxillary excision con- 

 stitutes the preanal lobe. 



The pygidium. — The tergite or dorsal wall of the last segment of the 

 abdomen. 



The hypopygium. — The sternite or ventral wall of the last segment 

 of the abdomen. 



The legida. — The scale-like plate overlapping the base of each front 

 wing. 



The corbicula. — A smooth area on the outer surface of the tibia of 

 the hind legs margined on each side by a fringe of long curved hairs. 



KEY TO THE SUBORDERS OF THE HYMENOPTERA 



A. Base of the abdomen not slender but broadly joined to the thorax. 



B. Antenna- inserted between the eyes above the base of the clypeus with the 

 bases of the antennae exposed; front wings with the transverse part of vein 

 Mj present or if wanting (Hylotoma) then vein R 4 is present in the hind wings 



