26 Key to Families of North American Insects. 



61. Wings folded once longitudinally when at rest; first discoidal cell in fore wings 



extraordinarily lengthened, much longer than the submedian; antennae 



distinctly elbowed 62 



Wings not folded when at rest 63 



62. Tarsal claws simple; mandibles not grooved on outer side; social species, con- 



structing paper-like nests (PI. 3, fig. 53). (Polistes [Paper- wasps], Vespa 



[Hornets and Yellow-jackets]) VESPER 



Tarsal claws with one or more teeth beneath; mandibles with grooves exter- 

 nally; solitary species (PI. 3, fig. 59). (Odynerus, Eumenes [Potter- wasps].) 



EUMENUXE 

 1$3. Second ventral segment not separated from the first by a strong constriction 



or transverse furrow 64 



Abdomen with the second ventral segment separated from the first by a strong 

 constriction or transverse furrow; legs very often formed for digging. . . .66 



64. Legs, especially the hind pair very much lengthened, the hind femora attaining 



the apex of the abdomen or extending beyond, tibiae and tarsi nearly always 

 spiny or serrate; middle tibiae with two spurs. (Pseudagenia, Psamm6ch- 

 ares (= Pompilus), Pepsis, Ceropales.) 



(CEROPALID&, POMPlLIDfi) PSAMMOCHARID^E 



Legs much shorter, the tips of the hind femora reaching not or only slightly 



beyond the middle of the abdomen; tibiae and tarsi smooth 65 



65. Metanotum posteriorly concave; antennae enkrged at the tip or clubbed, the 



club joints more or less fused. (Masaris, Pseudomasaris, Euparagia.) 



MASARIDJE 



Metanotum truncate or rounded behind; antennae not thickened apically, 

 none of the joints fused. (Sapyga, Eusapyga.) SAPYGID^ 



66. Middle coxae separated (usually widely so) by a bilobed or triangular prolonga- 



tion of the mesosternum 67 



Middle coxae contiguous, not separated by the mesosternum 69 



67. Tarsal claws cleft; male hypopygium ending in an upturned spine 68 



Tarsal claws simple; eyes emarginate within; hypopygium of male ending in 



three spines; usually large, brightly colored wasps (Scdlia, Elis.) SCOLED-Si: 



68. Male with the pygidium deeply emarginate at apex, the eyes emarginate within> 



the stigma narrow; female with the radial cell in the fore wing closed and 

 often separated from the costa (PI. 3, figs. 48, 49). (Myzine.) MYZINID^E 

 Male with the pygidium entire, the stigma broad; female with the radial cell 

 in the fore wing usually open and the first discoidal cell not elongated; eyes 

 entire in both sexes. (Tiphia, Paratiphia.) TIPHIID^; 



69. Hind wings with an anal lobe, separated by a deep linear notch 70 



Hind wings without an anal lobe, at most obtusely emarginate on the posterior 



basal margin 71 



70. Fore wings with the radial and the first and second discoidal cells very long, 



each fully four times as long as high; abdomen with a long, claviform petiole; 



rare West Indian insects. (Rhopalosdma.) RHOPALOSOMATID^; 



Fore wings of a different conformation; abdomen either petiolate or sessile. 

 (Myrmdsa, Chyphotes.) Males of the MYRMOSHXE 



