2. NOMADA. 115 



In small examples of the female the stripes on the thorax are 

 sometimes quite obliterated, and the scutellum has only two minute 

 red spots ; the yellow markings on the abdomen also become more 

 or less obsolete. The species is parasitic on Andrena bucephala. It 

 has not to my knowledge been found in company with any other 

 insect. A large colony of the Andrena formerly existed near High- 

 gate Archway, where the Nomada was very abundant. 



5. Nomada bridgmaniana. 



N. atra ; labio, clypei margine antico, mandibulis antennisque fer- 

 rugineis ; scutello punctis duobus tegulisque ferrugineis ; abdo- 

 mine ferrugineo, maculis duabus rotundatis flavis notato. Mas 

 clypei margine antico, labio mandibulisque flavis ; abdomine fer- 

 rugineo, flavo fasciato. 



Female. Length 3|-4 lines. — Black ; the mandibles, labrum, ante- 

 rior margin of the clypeus, and the flagellum ferruginous ; two 

 black spots on the clypeus and three or four of the basal joints of 

 the flagellum black, or fuscous above. Thorax, the tubercles bright 

 yellow ; two ferruginous ovate spots on the scutellum ; wings 

 subhyaline, the nervures fusco-ferruginous, the tegulae light ferru- 

 ginous ; the anterior legs with the apex of the femora, the tibiae, 

 and tarsi ferruginous, the tibise with a black stain behind ; the 

 intermediate and posterior legs with the extreme apex of the 

 femora, the base and apex of the tibiae, and the tarsi ferruginous ; 

 the basal joint of the posterior pair black. Abdomen, the base 

 black and a narrow black line at the apical margin of the first 

 segment, and a transverse narrow fuscous fascia a little before the 

 apical margin of the three following segments ; an ovate yellow 

 spot on each side of the second segment. B.M. 



Yar. ft. A more or less distinct double lunate yellow spot in the 

 middle of the fifth segment. 



Yar. y. A very minute yellow spot on each side of the third seg- 

 ment. 



Yar. <J. The spots on the scutellum yellowish. 



Male. Length 4 lines. — Black; the flagellum ferruginous and more 

 or less black or fuscous above ; the face anteriorly margined with 

 yellow, from which a narrow yellow line runs up to the margin of 

 the eyes as high as the insertion of the antennae ; the labrum and 

 mandibles yellow. Thorax with a thin hoary pubescence ; the 

 posterior margin of the tubercles yellow, as well as the outer mar- 

 gin of the tegulae ; the anterior legs of a reddish yellow in front, 

 all the tarsi more or less ferruginous, their basal joint stained 

 more or less black above. Abdomen ferruginous, with the base 

 black ; a narrow yellow interrupted band on the first segment in 

 the middle ; the two following have broader bands at their basal 

 margins, the first and sometimes the second also interrupted in the 

 middle, towards which they are slightly attenuated ; the three 

 following segments have narrow yellow bands. B.M. 



i2 



