FIELD BOOK OF INSECTS. 



4. Wings folded longitudinally when at rest (They are 

 indistinctly so in the MASARID^E of our West, which have 

 the end joints of the antennas thickened and more or less 

 fused) ; first discoidal cell much longer than the submedian ; 

 antennas distinctly elbowed 5. 



Wings not folded when at rest 6. 



5. Middle tibiae with one spur at apex; tarsal claws 

 with one or more teeth EUMENID^E (p. 428). 



Middle tibias with two spurs at apex; tarsal claws 

 simple YESFID.E (p. 430). 



6. Legs long, the hind femora reaching to or beyond 

 the apex of the abdomen; tibiae and tarsi nearly always 

 spiny or serrate ; middle tibias with two spurs 



PSAMMOCHARID^E (p. 428). 



Legs of usual length 7. 



7. A strong constriction or transverse furrow between 

 the first two segments of the abdomen, beneath 8. 



No such furrow; clypeus nearly, or quite, as long 

 as wide; margin of eyes indented. SAPYGID.E. Sapyga 

 is the only Northeastern genus; in centrata the yellow line 

 on inner orbits extends beyond the top of the eyes, and in 

 americana it does not. They are parasitic on bees and 

 wasps. 



8. Middle coxae usually widely separated by a bilobed or 

 triangular prolongation of the mesosternum ; tibias usually 

 flattened, with bristles exteriorly SCOLIID^E (p. 427). 



Middle coxae touching 9. 



9. Hind wings with an anal lobe, separated by a deep, 

 narrow notch. With three submarginal cells and no 

 upturned spine at apex of abdomen: male MYRMOSID/E; 

 the only species in the Northeast is Myrmosa unicolor. 

 With two submarginal cells and an upturned spine at 

 apex of abdomen: METHOCID^E, of which Metlioca stygia 

 is the only northeastern species. 



Hind wings without an anal lobe, at most obtusely 

 indented; body hairy, the hairs often brightly colored. 



Male MUTILLID.E (p. 427). 



10. Back of thorax without visible sutures 



Female MUTILLID/E (p. 427). 



Back of thorax with one suture. Female MYR- 

 MOSID.E (see 9). 



426 



