290 IIYMENOPTERA ACULEATA. 



longer tlian wiclOj but tlio third joint of the antenna) is much 

 shorter in proportion to the fourth, this in the $, looked 

 at from beneath, is not half, and in the ? scarcely more 

 than half the length of the fourth ; the ? is without the 

 pale sides of the face so characteristic of succincta and 

 se^efasciaia ; the eighth ventral segment of the ^ has 

 its apical process more slender, the sides near the apex 

 ■with finer paler spines, and the posterior coxre are less 

 densely hairy ; the tibias in both sexes are armed with 

 spines round the apex exteriorly, these are fine and long 

 in the <?, short and dark in the ? . 



L. 10-13 mm. 



Generally distributed and not uncommon in April and 

 May, parasitic probably on several spriug species of 

 Andrena. 



This species varies much in colour, and in the extent of 

 the yellow; sometimes the basal segment is banded with 

 red. 



N. alternata, Kirby (Marshamella, Kirh.). — Exceed- 

 ingly like lineola but differing in the following particulars ; 

 the third joint of the antennte is longer, and the fourth 

 shorter, so that the third joint in the c? is more than half 

 as long, and in the $ almost as long, as the fourth. The 

 tegulse are ferruginous, though occasionally flavous in the 

 J', in which sex the tibisc have a black streak posteriorly; 

 in the ? the apical spines of the tibiae are pale, not 

 black. 



L. 10-13 mm. 



Perhaps the commonest spring species, and generally dis- 

 tributed. Parasitic on Andrena nigrowuea and atricejjs and 

 probably on others also. F. Smith once observed it in 

 the burrows of Eucera. Mr. Frisby has a very curious ? 

 example of this species which has the coloration of the 

 cj , and the abdomen distorted ; possibly this may be the 

 effect of stylopization, but I know of no other record of a 

 species of this geuus being affected by this parasite. 



