ART. 9 TWO-WINGED FLIES OF TRIBE MILTOGRAMMINI ALLEN" 35 



has had this form under observation at frequent intervals during the 

 past tliree seasons, and has been able to gather some information on 

 its life cycle and ecology. 



Adults are generally present throughout the warmer months. In 

 Ohio, Mississippi, and the District of Columbia, where this species 

 has been under observation, it was found to be more widely dis- 

 tributed over the terrain than any other species of Senotainia. It 

 occurs, however, most commonly over barren sandy soil such as is found 

 along river banks, and on denuded ground, such places being sought 

 out also by the fossorial Hymenoptera with which it is associated. 

 The adults are not often found on rank vegetation except when 

 attracted by the blossoms of certain plants, but they visit in con- 

 spicuous numbers, a considerable number of flowers including 

 Erigeron, Anthemis cotula, and Euphorhia corollata. In the southern 

 states, in early fall, they are attracted in large numbers to cowpeas, 

 where they secure some food substance at the tip of the pod-bearing 

 stalks. They frequently appear on Erigeron and cowpeas, even when 

 these occur in dense stands on low rich ground at considerable dis- 

 tances from barren soil. 



Few published records can be found concerning the host relation- 

 ships of this species. There is one record of its issuance from a nest 

 of Sphecius speciosus}^ It is also reported as having been reared 

 from the common army worm,^'^ but this is so definitely at variance 

 with the usual activity of this species and its allies as to be decidedly 

 questionable. In a recent interesting article on the "ovipositional" 

 habit of trilmeata,'^^ Curran mentions other species of fossorial Hy- 

 menoptera, none of which were linked with this species in a wholly 

 convincing manner. The writer has reared several specimens from 

 the nests of Bicyrtes quadrifasciata. Prof. J. B. Parker secured 

 several specimens from a nest of Bicyrtes ventralis. The three wasps 

 from which it has been reared are Bembicidae which burrow in the sand. 

 One stocks its nest with flies, largely Muscoidea, the other two with 

 Hemipterous nymphs. Bembicid wasps, according to the writer's 

 observations, are never as abundant as trilineata adults; therefore it 

 seems probable that the latter will be found by further observation to 

 issue from the nests of several other common species of Hymenoptera. 



Professor Parker has submitted the following information regard- 

 ing the rearing of trilineata from Bicyrtes ventralis at Washington, 

 D. C. On June 13, 1914, the wasp ''was discovered storing a nest 

 with nymphs of a Hemipterous insect. It was marked and was 

 opened on June 20, 1914. It contained the remains of seven bugs 

 and ten fly puparia. No trace of the larval wasp was found. The 



i» Coqumett, U. S. Bur. Ent, Tech. Ser., No. 7, p. 20, 1897. 

 20 Forbes, Psyche, vol. 6, p. 467, 1893. 

 " Can. Ent., vol. 55, p. 174, 1923. 



