102 



32. Tetralonia crassipes, Friese. This bee is especially 

 numerous along the foot of the primary ränge of the Cor- 

 dilleras but appear to occur only singly out on the lowlands. 

 Both sexes go chiefly on Baccharis marginalis var. coeru- 

 lescens; female has been taken also on Cucurbita. 



In the beginning af 1907 I discovered a very curious 

 case with this species. Towards the evening of the lOth of 

 January, when in Chacras de Coria, I was surprised to find 

 cTcT sitting in close masses amongst the branches af Aspa- 

 ragus. The number of individuals in each clump was varying 

 from 3 to 8; they were extremely drowsy and allowed them- 

 selves to be knocked into the collecting bottle, without 

 attempting to fly away. This was repeated again the next 

 evening. I am almost positive that the homeless rfcT clump 

 themselves together in this manner to protect themselves 

 against the cold of the nights, which here at an elevation 

 of 2500 ft. and with clear night sky can be quite noticeable. 



I have also noticed a similar occurrance with Centris 

 tricolor (see under this species). 



33. Tetralonia flavitarsis var. bicincta, Friese. Was al- 

 most without exception, and in both sexes, taken on Hoff- 

 manseggia falcaria Cav. During my first journey in 1904 — 05 

 I found this species building in large colonies on steep 

 claybanks at Santa Rosa. 



34. Tetralonia fervens, Sm. Chiefly on Baccharis mar- 

 ginalis var. coerulescens, although amongst other plants also 

 on Cucurbita. 



35. Tetralonia zebra, Friese. This species is most cer- 

 tainly a mountain insect. In any case I have never found 

 it except in the mountains above Mendoza, where it occurs 

 commonly in both sexes and Visits many different plants, 

 e. g. Senecio sp. 



36. Tetralonia bipunctata, Friese. An autumn species and 

 probably also a mountain insect, showing preference for 

 Loranthus (Phrygilanihus) cuneifolius R. & P., although if 

 I remember correctly also on Cucurbita. 



37. Tetralonia corvina, Friese. I found the females with- 

 out exception on Hojfmanseggia falcaria. The males were 

 also on the same plant, although I cannot remember, if I 

 met with them on other plants. 



39. Tetralonia Jenseni, Friese. On various low plants. I 

 cannot remember noticing that they preferred any one species 

 for another. 



43. Ancyloscelis nigerrima, Friese. I have seen specimens 

 of this large species flying into its nest in the hard stony 



