NORTH AMERICAN GEOTRUPINAE — ^HOWDEN 225 



On Apr. 19, 1951, in the center of a burned-over area in a sandy 

 pine, deciduous woods at Faison, N. C, two small push-ups of yellow 

 sand were noted. One of these yielded a well-armed male at a depth 

 of 5 inches. Under the second push-up a pair of darlingtoni was found 

 in a small cell at a depth of 11 inches. A few inches away, apparently 

 not connected to either of the two burrows containing adults, another 

 small cavity was found at a depth of llK inches. In the cavity was a 

 single elliptical egg, 2.4 mm. long by 1.5 mm. wide. Just above the 

 cavity containing the egg (pi. 14, fig. 1) was the food supply. This 

 consisted of very finely divided surface humus mixed with sand packed 

 into the slightly sinuate burrow. 



Through the kindness of Dr. J. W. Fitts, SoU Testing Laboratory, 

 North Carolina Department of Agriculture, a portion of this black 

 humus used for larval food by darlingtoni was analyzed. The analysis 

 was made using a modified Walkley Black procedure to show the 

 amount of readily oxidizable organic matter that the material con- 

 tained. The larval food cell was found to have 3.44 percent organic 

 matter compared to 0.16 percent found in the surrounding subsoU. 

 Normally, the surface soil in the area contained only about 1 percent 

 readily oxidizable organic matter. It would appear that, if the adult 

 beetles actually did not concentrate the humus in the burrows, they 

 at least chose areas that have a very high surface concentration of 

 organic matter in which to burrow. 



The egg collected at Faison was carefully transferred to a metal 

 salve box along with the food material provided and was taken into 

 the laboratory. Eleven days later, on Apr. 30, 1951, the larva emerged 

 from the egg and the following day began feeding on the humus. 

 Growth was quite rapid, the larva becoming a second instar on May 18 

 and a third ins tar on June 14. Several days after this the larva was 

 preserved. 



On June 19, 1951, the same area in the Faison woods where the egg 

 had been collected was revisited. A fresh burrow was noted only a 

 foot away from the previous excavation. The burrow yielded a single 

 female darlingtoni and nothing else. No other activity was indicated 

 by the surface push-ups, but the area of excavation was extended. 

 At a depth of 10 inches in a rather winding burrow five-sixteenths of 

 an inch in diameter, packed with the finely divided black humus, a 

 third-stage larva was found. 



Further digging yielded seven additional larvae in the same type 

 of slightly sinuous burrows packed with surface humus. The food 

 cell varied from 6.5 to 8 mm. in diameter and from 2 to 3 inches in 

 length. The larvae were found at depths of 8%, 8K, 9, 9K, lOK, UK, 

 and 12 inches. All the larvae were third-stage. Two specimens 

 had moved below the food material in the burrow and made a pupal 



