AKT. 9 TWO-WINGED FLIES OF TRIBE MILTOGRAMMINI ALLEN 19 



South America, Other species (SpJiecapata) are ■widely distributed 

 OTer Europe. So far as known, the European and New World forms 

 are distinct. In North America the genus ranges from British 

 Columbia and Ontario on the north, to Panama, and is represented 

 also in some of the West Indian islands. This genus appears to be 

 best represented in the fauna of the south and southwestern states, 

 where as many as six species may be present in the same general 

 locality. Northward the number diminishes, and southward in 

 tropical America, also, fewer species are known, though perhaps 

 because that region has been less thoroughly worked. Judging 

 from its presence in collections, the individuals of the genus Senotainia 

 are nearly if not quite as abundant as individuals of all other Milto- 

 gramminid genera combined. In the collection of the writer which 

 is largely from Mississippi and Ohio, over seventy per cent of aU 

 Miltogramminae are Senotainia, and Mefopia, with about seventeen 

 per cent, is the genus which most closely approaches it in numbers. 

 A somewhat similar ratio exists in the other large collections studied. 



The adults of several species of Senotainia are attracted to flowers. 

 Several species of flowers may be visited by one species of fly. 

 Compositae appear to be favored, but the blossoms of other groups 

 are also visited. The writer has never taken them on the blossoms 

 or foliage of trees or high shrubs. It has been noted that in species 

 of Senotainia that visit flowers, the proboscis is long and slender, 

 while in Metopia, Sphenometopa, Phrosinella, and other genera in 

 which the adults have never been taken on flowers, the proboscis is 

 veryrshort and stout. 



The members of the genus Senotainia, so far as known, are bio- 

 logically superimposed on fossorial Hymenoptera, principally as 

 commensals living on the food provided by the wasps for their young, 

 frequently eliminating the grub of the wasp either by producing 

 unsuitable conditions or by direct predatory act, but probably 

 never as a true endoparasite of the latter. The females deposit 

 large, active, naked larvae, probably in most cases, on or near the 

 paralyzed prey of Hymenopteron hosts, after it has been placed 

 in the burrow. The members of at least three families of Aculeata, 

 Bembicidae, Psammocharidae and probably Sphecidae are attacked 

 by Senotainia. All so attacked dig burrows in the soil, some of which 

 are provisioned with spiders, others with flies, Heteropteron nymphs, 

 or other Arthropod prey. From the rather limited rearing records, 

 it would appear that the larvae of Senotainia are far less exacting in 

 their food rec^uirements than typical Tachinids, in this respect much 

 more closely approaching the typical Sarcophagidae and Calliphori- 

 dae. The conjectures of Townsend'^ as to the larval habits of 



13 An. Ent. Soc, vol. 4, p. 140, 1911. 



