ANTS, BEES, AND WASPS. 



(a) TENTHREDINOIDEA. No marked constriction 

 between the thorax and abdomen, the abdomen being 

 broadly joined to the thorax; trochanters (the part between 

 the basal joint and the long femur) two-jointed. Saw- 

 flies; see p. 408. 



In the groups b to j there is a marked constriction 

 between the thorax and abdomen, the two being joined 

 by a relatively thin stem (petiole or pedicel), which may 

 be either very short or long. 



(b) CHALCIDOIDEA. Usually less than an eighth of 

 an inch in length and metallic in appearance; trochanters 

 two-jointed; antennas elbowed, with one or more ring-like 

 segments between the shaft and lash; wings, if any, with 

 but few veins; wingless forms with indistinct or no ocelli; 

 female's ovipositor issuing from the ventral surface of the 

 abdomen some distance before the tip. See p. 414. 



(c) SERPHOIDEA. The Pelecinidae have one-jointed 

 trochanters; abdomen, and also antennae, long and slender; 

 black ; front wings with no closed submarginal cells. The 

 others have two- jointed trochanters; body not metallic, 

 usually black with sometimes brown or red; antenna? 

 straight or, if elbowed, without the ring-like segments; 

 the wingless forms with distinct ocelli; ovipositor issuing 

 from the tip of the abdomen. See p. 415. 



(d) CYNIPOIDEA. Trochanters two-jointed; antennae 

 with not more than 16 joints; front wings, if present, 

 without stigma (a thickening of the costal vein at about 

 two-thirds of the way along the front margin of the front 

 wing) but usually with one or more closed cells; antennas 

 straight; body "flea-like." See p. 414. 



(e) ICHXEUMONOIDEA. Trochanters two-jointed 

 (except in rare forms); antennas with more than 16 joints; 

 front wings, if present, with a stigma and one or more 

 closed cells; antennas straight. See p. 411. 



In groups / to j the trochanters are always one-jointed. 



(/) CHRYSIDOIDEA. Only three abdominal segments 

 visible; bright green, bluish, or golden; antennas short and 

 elbowed; front wings with no closed submarginal cells. 

 See p. 424. 



(g) FORMICOIDEA. - First apparent abdominal seg- 

 ment (sometimes also the second) forming a lens-shaped 



407 



