101 



stony, and I had nothing eise with me than a pocket knife 

 to work with, I was not able to dig the nest up. Round the 

 hole lay a ring of earth. Both sexes of this species were 

 common as late as the end of March. 



Nomia Jenseni, Friese. As no. 22 but much rarer. It 

 was discovered for the first time at Santa Rosa during my 

 first expedition. 



23. Camptopoeum flaviventre, Friese. Always upon Grin- 

 delia pulchella. Dun. It could nearly always be found toge- 

 ther with a little Buprestid, which at a little distance had a 

 certain colour resemblance to it, in the large golden flowers. 



24. Camptopoeum ochraceum, Friese. Both sexes of this 

 species were always taken upon the yellow flowers of cactus 

 (Opuntia), almost always in Company with Psaenythia bifas- 

 data, Friese (see no. 28). 



25. Psaenythia philanthoides, Gerst. Seemed to show 

 preference to Solanum elceagnifolium Cav. and Physalis 

 (viscosa ?). 



26. Psaenythia picta, Gerst. Together with the last. 



27. Psaenythia laticeps, Friese. As the preceeding. 



28. Psaenythia bifasciata, Friese. Was principall yonly to 

 be found up on the primary ränge to the Cordilleras de 

 Mendoza, but here in large numbers. Is was only found on 

 cactus (Opuntia and Echinocactus) and nearly always toge- 

 ther with Camptopoeum ochraceum, Friese (no. 24). As soon 

 as these two bees noticed the slightest disturbance, even a 

 sound, they would fly like lightning out of the blossom, so 

 that to obtain the Contents of a flower it was necessary to 

 very carefully shut the opening to keep the bees in. 



29. Xylocopa brasiiianorum, L. This common and widely 

 distributed bee went to several different plants, although chiefly 



' Ccesalpinia brea R. P. in the spring (both cT and $) and 

 later (but only females) Solanum elceagnifolium, and also 

 in the autumn, similarly only females, on Phaseolus. Mr. P. 

 Jorgensen informed me that he has found them sometimes 

 even building in the bamboo rods used for roofing. The 

 females sting very badly, causing pain for two or three 

 days. 



30. Xylocopa splendidula, Lep. Visits amongst others 

 Solanum elceagnifolium. 1 have found them building in old 

 poplar branches (Populus pyramidalis Roz.). This Xylocopa 

 (the one sex ?) can often be seen on hedges of this poplar, 

 „resting" quite still in ihe air for a few seconds just like a 

 Syrphus. 



31. Ceratina volitans, Schrottk. As no 11, but much 

 scarcer. 



