104 



In the lowlands I observed this bee visiting Solanum 

 elceagnifolium and in the mountains Acacia and Mimosa. 



55. CentFis nigerrima, Spin. Very rare in this district. 

 On Hojfmanseggia falcaria Cav. 



56. Centris nigrivenlris, Burm. This species was in the 

 hottest summertime quite common at Pedregal. I have never 

 Seen it visit other flowers than Hojfmanseggia falcaria. 

 Both sexes of the bee had the pecuHar habit of „standing 

 quite still" before taking a plunge into the blossom it had 

 determined on. 



This species, together with C iricolor, was first descri- 

 bed by Burmeister in the „Stett Ent. Zeitschr." In the Latin 

 diagnosis of the species the hair on the thorax and the first 

 Segment of abdomen is stated as „viridi — cinereo — hirtis", 

 which describes it pretty accurately, but in the detailed 

 German description this colour is stated to be „grünlich- 

 grau", which is hardiy suitable. In all the many specimens, 

 I have collected of this handsome little bee the colour of 

 the hair on these two parts is of a clear lemon yellow or 

 greenish sulphur colour. 



57. Centris tricolor, Friese. Generally distributed. All the 

 specimens (both (^ and §) that I have taken or seen were 

 on Hoffmanseggia falcaria. As with all the other Centris 

 species the flight is like lightning and the time of staying 

 in a flower only a few seconds. 



As to this species I noticed a similar case as mentioned 

 with no 32 (Tetralonia crassipes), but curiously enough 

 here were only ?$. 



When I was at Chacras de Coria in the beginning of 

 January 1907 I noticed this species every evening flying in 

 numbers round a peach tree, although on this occassion I 

 did not investigate the matter, Later on, on the 16th Febr. the 

 same year, I returned to the same place, and at about six in 

 the evening I noticed that a number of bees were hidden 

 among the leaves of a little branch of the same peach tree. 

 It was undoubtedly the same branch that had been used as 

 night lodgings the whole time. The bees (all $$) sat pretty 

 close to each other, while others tried to come in, humming 

 rigourously, apparantly fighting, and in the usual flight ofa 

 Centris. A great portion (19 specimens) ended their days 

 in my collecting bottle, and several flew away. The next 

 evening only two specimens applied for night lodgings, so 

 I presume that the Company had „broken up". During the 

 next few days we had a great deal of rain, rather an un- 

 common occurrance for the district, so that further investiga- 



