910 AN INTRODUCTION TO ENTOMOLOGY 



D. The pronotum extending laterally directly to the tegulae, where its 

 lateral prolongations do not terminate in the form of a rounded "pos- 

 terior lobe" covering the spiracles. 



E. Cell M4 of the forewings longer than cell Cu + Cui. Lateral pro- 

 longations of pronotum forming a posterior angle which lies above the 

 tegular. Wings usually longitudinally plaited, p. 948 . . . Vespid^e 

 EE. Cell M4 of the forewings shorter than cell Cu + Cui or absent. 

 Lateral prolongations of pronotum bluntly rounded, not lying dorsad 

 of the tegulae. Wings never longitudinally plaited. 

 F. Mesopletua divided by a transverse suture into an upper and 

 lower plate. First and second abdominal stemites imbricate. 

 Coxae very large and long; the legs long and usually distinctly 



spinose. p. 933 PoMPiLiDiE 



FF. Mesopleura not divided by a transverse suture. Coxae and legs 

 not unusually long. 



G. First abdominal segment united by a ball and socket joint to the 

 second, and itself forming an almost completely separated 

 "scale" or "noae." Hypopygium of male unciform. Females 

 winged; a worker caste present. (Some more primitive genera of 



ants.) p. 937 F0RMICID.E 



GO. First abdominal stemite attached to the second by a suturi- 

 form articulation or more or less imbricate, the first segment not 

 forming a "scale" or "node" between the propodeum and the 

 gaster.* 



H. Mesosternum not forming with the metastemum a con- 

 tinuous plate overlying the bases of the hind and middle 

 coxae. Axillary excision of the hind wings in normal position, 

 apex of male abdomen without three retractile spurs between 

 the last tergite and its sternite. 



I. Vein M4 + Cui of the forewings opposite vein m-cu or 

 nearly so. Second and third tarsal segments of the female 

 not dilated. 



J. Mesosternum with two laminae which overlie the bases of 

 the middle coxae. 



K. Little or no constriction between the first and second 

 abdominal sternites, which are almost or somewhat 

 imbricate. A trace of a vein (base of Rs) often divides 

 the first submarginal cell (R + 1st Ri)). Hypopygium 

 of male not unciform. Apex of the marginal cell (2d Ri 

 + R2) distant from the wing apex by not more than the 

 length of the cell. Both sexes winged, p. 935. . . 



Anthoboscid^ 



KK. First and second abdominal sternites separated by a 

 strong and distinct suturiform articulation and either 

 the hypopygium of the male is unciform, or the females 

 are wingless and carried about by the males in mating. 

 L. Hypopygium of the male not unciform; but some- 

 times it is tridentate at apex with the middle tooth 

 long and spiniform. Females apterous and carried 

 about by the males in mating. First submarginal 

 cell usually divided by a weak vein (base of the 



radial sector), p. 935 Thynnid^ 



LL. Hypopygium of male unciform, known American 

 females winged. First submarginal cell not divided 

 (base of Rs wanting). 



M. Diurnal insects with normal eyes and ocelli. 

 Females winged. (Tiphiinae). p. 936. TiPHiiDiE 



*Some genera of Mutillidae in which the first or first and second abdominal 

 segments are more or less nodose may be recognized as falling in this category by 

 the unciform hypopygium of the males, the apterous females, and the absence of a 

 neuter caste. 



