26 PROCEEDINGS OF THE NATIONAL MUSEUM vol. G8 



to other species of the ruhriventris group known to be present in 

 the Great Lakes region. 



The writer has taken the female in midsummer, on sandy, barren 

 spots in open pasture, and the males in large numbers on the flowers 

 of Erigeron, in early spring. One adult has been reared from nests of 

 Bicyrtes quadrifasciatus stocked with Heteropteron nymphs, from 

 Ada ton. Miss. A small maggot was discovered on July 17 boring 

 into a paralyzed nymph in the nest of the wasp taken to laboratory 

 on July 15. By the following day it had dismembered the nymph 

 and bored into the sand beneath to pupate, and on July 28, the fly 

 emerged. The last part of the larval stage was passed in burrowing 

 in and out of the putrid material, like a typical Sarcopliaga maggot. 



Prof. J. B. Parker has made some interesting observations on the 

 biology of this species in connection with his work on wasps at Wash- 

 ington, D. C. One female, labeled, ''Parker Note No. 18," was 

 captured after invading the burrow of Oxyhelus quadrinotatus Say 

 on June 20, 1914. In another observation, "Parker Note No. 27," 

 he states that on June 24, "a solitary wasp was discovered entering 

 her nest with a grasshopper. A fly dashed into the nest after the 

 wasp and was captured as it came out. The nest was opened at 

 once and found to contain three completed brood chambers, and 

 one incompleted. The incompleted brood chamber contained two 

 grasshoppers each ol which bore fly larvae." In one of the completed 

 chambers, with the partly-consumed stock of grasshoppers, ''was 

 found a single fat dipterous larva which was taken to the laboratory 

 and placed in a breeding cell." On July 12, 1912, the fly emerged. 

 The wasp was not identified. 



SENOTAINIA VIGILANS Allen. 



Senotainia vigilans Allen, Occas. Pap. Bost. Soc. Nat. Hist., vol. 5, p. 81^, 

 1924. 



Type.— Male, Cat. No. 27231, U. S. N. M., from Adaton,, Miss. 



This species closely resembles litoralis Allen from which it dift'ers 

 in having a large amount of red on the abdomen, while the latter is 

 constantly black throughout. In vigilans there is usually but one 

 proclinate orbital (pi. 4, fig. 23) and in the male, the sides of the fifth 

 sternite are lobiform, and the hind femur bears villous hairs equalling 

 the thickness of the femur on the proximal third of the under suiface. 

 Some specimens of vigilans vary toward ruhriventris. Males of 

 vigilans may be readily distinguished by the tips of the outer forceps 

 (pi. 2, fig. 11) which are angular and hooked towards tip of inner 

 forceps, by the lobiform fifth sternite and the villosity of the hind 

 femur. In both sexes of vigilans, the bucca and front is wider, the 

 arista more extensively thickened than in ruhriventris. 



Two mature females have been dissected and the reproductive 

 organs examined (pi. 4, fig. 22). The outstanding morphological 



