no. 2173. A REVISION OF THE BEMBICINE WASPS— PARKER. 133 



the second was constructed. If unfavorable weather interferes with 

 the work of the wasp before the nest is completely provisioned, she 

 will return to it later and complete the store of food necessary to 

 develop her offspring. Under such circumstances I have observed 

 Bicyrtes ventralis carrying bugs into a nest that contained a half- 

 grown larva. On one occasion, after a few days of adverse weather 

 and while the sand was yet wet, I observed a female ventralis open 

 and enter a nest but without carrying in a bug. After a few minutes 

 spent inside she emerged and sealed up the nest. I at once digged 

 up the nest and found within it a half-grown larva, several untouched 

 bugs, and the remains of several more that had been devoured. I 

 placed the contents of the nest in a breeding cell and in due time the 

 larva completed its growth and spun its cocoon. Here it would 

 seem that the mother wasp, after an absence of two or three days 

 caused by rainy weather, visited the nest for the purpose of ascer- 

 taining whether the larva had been sufficiently provided for. The 

 fact that she sealed up the nest after the inspection indicates that she 

 found conditions satisfactory and my subsequent investigation 

 proved the correctness of her good judgment. 



On June 13 I marked a nest in which the wasp was busily storing 

 bugs. I digged this nest up on June 20 and found the larva safely 

 inclosed in its cocoon. It had passed from egg to mature larva 

 within a week. On June 23 a wasp was observed storing her nest. 

 While under observation she completed the provisioning of this 

 brood chamber and sealed it up. She at once constructed a second 

 brood chamber leading off from the same entrance as the first. She 

 placed a few bugs in this, but night came on before the work was 

 complete. She resumed her task on the morning of June 24, com- 

 pleted provisioning the nest and then sealed it. I then marked the 

 nest, but it was not again visited by the wasp. On June 26 I digged 

 up the nest and placed the contents of the two brood chambers in 

 separate breeding cells. The larva from the brood chamber that 

 was first constructed completed its feeding and began forming its 

 cocoon on June 28; the one from the second chamber, on June 30. 

 The results of further investigations show that the egg usually 

 hatches from forty-eight to seventy- two hours after being deposited. 

 As in the case of Bembix the larva moves up to the top of the empty 

 eggshell and remaining with its posterior end attached thereto makes 

 use of this vantage point to reach for food in all directions. The 

 number of bugs placed in a brood chamber varied from 3 to 11. In 

 cases where the number of bugs was large the individuals were 

 smaller than where the bugs were less numerous. The larva com- 

 pletes its feeding in from three to five days, so that the time from 

 newly-laid egg to encased larva is approximately one week. 



