JUNE, '21] SCIENTIFIC NOTES 307 



A. Rohwer as Nomia nortoni Cress. Emergence was at first localized, but in a few 

 days the bees appeared in all parts of the fields, although more numerous in some 

 places than others. Ma.ximum abundance continued for about a week, after which 

 their number gradually decreased. All were gone in about 15 days, disappearing 

 as suddenly as they had appeared. The report of the grower as to the condition 

 of the sweet potato crop v\-as found to be correct. The plants were somewhat shriv- 

 eled and plainly showed the lack of moisture. On the side of the field first attacked 

 by the bees they had assumed a yellowish appearance. Some were almost uprooted 

 by the bees in their mining. 



Nomia nortoni is slightly larger and darker than the honey bee. Unlike many 

 mining bees, it does not construct common burrows with branches terminating in 

 a single cell. These tunnels more often than not terminate in a single nest which 

 consists of from 4 to 12 cells, the majority examined containing 6 to 8 cells. Most 

 of the burrows ran perpendicularly into the ground for from 8 to 48 inches, usually 

 ranging from 18 to 24 inches in depth. Only two burrows were found as deep as 

 48 inches. Three instances were observed where the same tunnel from the surface 

 appeared to have been used as a passage from two nests, the second nest being about 

 8 inches directly below the first. The writer cannot be positive as to this, however, 

 as the nature of the soil and the close proximity of the bunows rendered diffltult 

 the tracing of any single tunnel all the way down to the nest. At the bottom of 

 the burrow, the nest proper was held in a pocket-like cavity, the walls of which 

 were at such distance from the brood cells as to render each readily accessible. 

 It was constructed of moistened and kneaded earth, irregular in outline and about 

 the size of a lemon. The walls of each cell in the nest had been tightly sealed and 

 glazed. A few dead bees were found in the cells, although the majoritv were emp- 

 ty- 



The writer has been unable to find the new home of these bees, but it is evident 

 that they did not deposit all over this plot, for no trace of bees was found in the 

 several holes that were dug. No doubt with the aid of a steam shovel the bees 

 could be located in a short time to ascertain the stage present at this time. The 

 nests appeared to have been tightly sealed before the bees emerged and their con- 

 struction showed that the builders possessed some ingenuity. The writer hopes 

 that he may be able to secure more data on this insect at a later date. The bees 

 caused the sweet potato crop in this locality to be a total failure. The plot could 

 not practically be irrigated from the small well after the bees had finished with their 

 tunneling of the soil, as the plat was a sandy loam soil underlaid with a stratum 

 of "caliche" (limestone) that would take up the water faster than it could be applied. 

 The bees did no other injury to the sweet potatoes than filling the soil full of bur- 

 rows, which prevented irrigation and later caused the plants to dry up. 



The pest was injurious to sweet potatoes in this locality in 1915, but at that time 

 the writer was able to secure only a single specimen, as the bees had practically dis- 

 appeared when he arrived on the ground. It appears that the bee prefers to de- 

 posit in soil that has been irrigated since no report has been received of it doing 

 damage to non-irrigated soil 



M. M. High 

 Entomological Assistant, Truck Crop Insect Investigations, United States Department 



oj Agriculture 



Subcortical Temperatures of Logs Exposed to Direct Sunlight. Diu-ing the past 

 year the attention of entomologists has been called to the fact that the temperature 



