1916.] 215 



Ent. Mo. Mag., the record of course being a gross error, as the 

 specimens were what were then called " dark forms " of ruficornis 

 (i.e., ruficornis proper). It still remains a question whether these 

 ruficornis were really parasitic on albicans or on some other host, the 

 burrows of which were intermixed with those of albicans, hnt of which, 

 during several occasions spent in collecting the ruficornis, I did not 

 see a single example. 



The fact that, while albicans and its true parasite bifida abounded 

 everywhere in the district, it was onlj^ in this one small spot and in 

 this one year that I found the dark-coloured ruficornis, inclines me to 

 the belief that some other Andrena, in spite of the time spent in 

 specially collecting the Nomada in this spot, was overlooked by me. 

 Looking over my records for past years, I find that in that particular 

 neighbourhood the only species of the Andrena varians group — the 

 group to which the ruficornis group is particularly attached — that 

 was ever collected, was A. helvola, and that this was of the rarest 

 occvirrence. Consequently I have some doubts whether some of the 

 supposed albicans burrows may not really have belonged to helvola, 

 though many of the former were seen entering their nests, but not one 

 of the latter. 



SYNOPSIS OF ? ? . 



1 (2) Abdomen brown or ferruginous, the base of the 1st segment black, the 



yellow spots of the 2nd segment lateral, extremely widely separated 

 from one another, 3rd segment Avith an extremely small spot on each 

 side or without spots ; scape of antennae black, the pronotal tubercles 



bright yellow xanthosticta Kirby 



(=lateraUs E. S. nee Smith). 



2 (1) If the scape of the antennae is wholly black and the abdominal mark- 



ings as above, the tubercles are not bright yellow. 



3 (4) Clypeus with a narrow apical red band, generally narrowest in the 



middle, or even entirely interrupted there; mesopleuraat most with 

 a small red spot in front behind the base of the front femora ; hairs 

 of the mesonotum much longer and more plentiful than in any of 

 the following. (Scape of antennae often wholly black ; mesosternum 

 rarely with red lines) borealis Zett. 



4 (3) Clypeus with the apical red band usually occupying at least half its 



length and often widest in the middle ; sometimes the whole clypeus 

 is red ; mesopleura with at least a large and conspicuous red macula, 

 or with a large one below and a small one above. 



5 (6) 2nd abdominal segment with lateral ovate or sub-triangular yellow 



spots, which are so widely separated inwardly that they do not 



