970 



AN INTRODUCTION TO ENTOMOLOGY 



arch without a median lobe. In most genera the middle tibiae have 

 a single apical spur and the second submarginal cell (Ro) is small 



and triangular; but in 

 some the middle tibiae 

 have two apical spurs 

 and cell R5 is four-sided. 

 These wasps burrow 

 in the ground ; some spe- 

 cies store their nests with 

 Homoptera, others with 

 Orthoptera. 



Our best-known rep- 

 resentative of this tribe 

 is the Cicada-Killer, 

 Sphecius speciosus. This 

 is a formidable insect, 

 measuring about 30 mm. in length (Fig. 1208). It is black, sometimes 

 of a rusty color, and has the abdomen banded with yellow. It digs 

 deep burrows in the earth and provisions each with a Cicada. Figure 

 1209 represents its wings. 



1208. — Sphecius speciosus. 



Mi + Ctix +Cu 

 Fig. 1209. — Wings of Sphecius speciostu 



Tribe STIZINI 



In the Stizini the transverse part of vein M is distant from the 

 stigma by two or more times the distance between the apex of 

 cell 2dR]-|-R2 and the apex of the wing; the labrum is usually 

 transverse, rarely long and pointed; the ocelli are normal; and the 

 middle tibiae are armed with two apical spurs. 



The species of the genus Stizus are gregarious, many individuals 

 building their burrows near together. The common and conspicuous 

 western Stizus unicinctus is believed to lay eggs in nests of Chlorion 

 {Priononyx) atratrum. 



