go Clarence E. Mickel 
Lyroda triloba Say. 
1837. Lyroda triloba Say, Bost. Journ. Nat. Hist., I, p. 372. 
1893. Lyroda triloba Fox, Proc. Acad. Nat. Sc. Phil., p. 533. 
1913. Lyroda triloba Williams, Kans. Univ. Sc. Bull., VIII, p. 174. 
Females 1: Lincoln, August (W. D. Pierce), on Euphorbia 
marginata. 
Lyroda subita Say. 
1837. Lyroda subita Say, Bost. Journ. Nat. Hist., I, p. 372. 
1893. Lyroda subita Fox, Proc. Acad. Nat. Sc. Phil., p. 533. 
1913. Lyroda subita Williams, Kans. Univ. Sc. Bull., VIII, p. 174. 
Males 19, females 17: Union (1), Omaha (22), Louisville (1), 
Ashland (1), Lincoln (2), Fairmont (1), West Point (1), Haig- 
ler (1), Mitchell (5) and Monroe Canyon (1); June 20 to 
August 19; visits flowers of Chamaecrista fasciculata, Melilotus 
alba and Physalis virginiana. 
LARRINI 
KEY TO THE GENERA 
1. Face along the inner eye-margin without a swelling or fold ........ 2 
Face with a more or less developed longitudinal swelling or fold along 
che “IMEr* Cye-Mageitt , 2 5..'.. vies ween cots. noida eine we One see 3 
2. Comb of anterior tarsi of female composed of very large flexible spines 
or bristles; pygidial area naked; hind ocelli oval; fore femora of 
the male always emarginate beneath the base .......... Tachysphex 
Comb of anterior tarsi of female composed of stiff rather short thorns; 
pygidial area entirely covered with pubescence; hind ocelli linear, 
hooked at upper end; fore femora of male either emarginate or 
simple. beneath near the, bases sass seek concen ene Tachytes 
3. Mandibles indistinctly dentate; pygidial area in female bare; pronotum 
hardly depressed beneath the level of the mesonotum; posterior 
margin of the pronotum nearly straight (transversely) ...... Larra 
Mandibles more or less bidentate within; pygidial area of female more 
or less pubescent 1.00.50 5¢.c2 fa femeee ot oc ee tee 4 
4. Pronotum not drawn under the mesonotum; propodeum shorter than 
the mesonotum; anterior femora of male emarginate near the base; 
pygidial area bare towards the base, but with short! stiff hairs at 
the apex an. Skee be eee eas cee ee Oe Larropsis 
Pronotum drawn under the mesonotum, especially at the sides; pro- 
podeum longer than the mesonotum; anterior femora of the male 
not emarginate near the base; pygidium pubescent in both sexes, 
Notogonidea 
408 
rs —- =” 
