538 U. S. NATIONAL MUSEUM BULLETIN 216 



cylindric or subcylindric; abdomen attached moderately low on pro- 

 podeum; female hind coxa without an internal groove for holding 

 ovipositor; tarsal claws simple; areolet present; apex of costellan vein 

 with about 5 or 6 strong hamuli; spiracle of first abdominal segment at, 

 or somewhat in front of, or behind the middle. 



This is a new tribe, composed of the genera Labium, Macrogrotea, 

 and Grotea. The series of 5 or 6 hamuli at the end of the costal vein, 

 exposed labrum, and the habit of parasitizing bees are among the 

 pecularities of the tribe. Grotea is the only genus in our fauna. 



Macrogrotea is in southern South America and Labium in the Aus- 

 tralian region. Orthognathella is a synonym of Labium (new synony- 

 my). We studied the type of the genotype of Orthognathella in Berlin. 



1. Genus Grotea 



Figure 307,a 



Grotea Cresson, 1864, Proc. Ent. Soc. Philadelphia, vol. 3, p. 397. Type: Grotea 

 anguina Cresson; monobasic. 



Front wing 4.5 to 10 mm. long; mandible with two apical teeth; 

 clypeus and labrum rather small; epomia absent; upper end of pre- 

 pectal carina near lower corner of pronotum; first abdominal segment 

 about 1.6 as long as hind femur, slender, upcurved, its spiracle be- 

 hind its middle. 



This genus contains a few species in North and South America. 

 It is parasitic in nests of bees. 



Key to the Nearctic species of Grotea 



1. Proces3 at lower end of occipital carina narrow at apex, in profile directed down- 

 ward and a little backward; basal area of propodeum about 1.4 as long as 



wide 1. anguina Cresson 



Process at lower end of occipital carina broadly rounded at apex, in profile 

 directed downward and rather strongly backward; basal area of propodeum 

 about 0.7 as long as wide 2. californica Cresson 



1. Grotea anguina Cresson 



Grotea anguina Cresson, 1864, Proc. Ent. Soc. Philadelphia, vol. 3, p. 398; cf, ?. 



Lectotype: ?, New Jersey (Philadelphia). 

 Biology: Graenicher, 1905, Ent. News, vol. 16, pp. 43-49. — Rau, 1922, Trans. 



Acad. Sci. St. Louis, vol. 24, p. 43; 1938, Ann. Ent. Soc. America., vol. 21, 



p. 383. 



Front wing 6.5 to 9.5 mm. long. Structurally similar to G. cali- 

 fornica except as stated in the key. 



Head yellow, suffused with fulvous behind, above, and on frons, 

 black behind occipital carina; mouth parts yellow; antenna light ful- 

 vous, with a fuscous band centered over its apical 0.68, beyond which 



