OF WASHINGTON, VOLUME XIII, 1911. 155 



ing their escape from the chorion and starting away in search 

 of hosts. I have noted the same with Varichceta ruficanda in 

 Massachusetts and with Sarcophaga in Peru. I believe that 

 it will be at once most convenient and most truly representa- 

 tive of the actual conditions to consider the deposition of all 

 tough or thick chorion eggs as oviposition, whether or not 

 they contain the more or less developed maggot; and the de- 

 position of maggots, whether naked or enveloped more or less 

 fully in a delicate chorion, as larviposition. The first are al- 

 ways specially provided, either by flat ventral surface, by 

 pedicel, or by heavy chorion carrying an abundance of cement 

 (as in the cuterebrine flies), for outside deposition and at- 

 tachment to surfaces as eggs. The last are not so provided 

 in any way, the intent of the act in their case being certainly 

 the deposition of living maggots for immediate activity. The 

 membraneous base by which the maggots of the leaf-larvi- 

 positing forms are attached to plant surfaces probably consists 

 of a part of the chorion, or perhaps the vitelline membrane, 

 or both, which adheres to the anal end of the maggot at birth, 

 being thus made use of by the maggot certainly at times, 

 though the latter may leave this base in search of a host. The 

 subcutaneous deposition of maggots is perhaps normally made 

 in choria. The subcutaneous deposition of eggs, to be noted 

 farther on, presumably made as eggs without any develop- 

 ment of the maggot, is indicated only in those forms with an 

 elongate egg and delicate chorion entirely unsuited for ex- 

 ternal attachment. 



Group II. Species depositing on the food of the host a 

 microtype egg containing the developed maggot and destined 

 to be swallowed. Fourteen identified species are mentioned 

 here, including the following genotypes which I have not yet 

 been able to dissect: Baiimhattcria goni<rfonnis, Cncphalia 

 bisetosa, Frontina Iceta, Spallanzania hebes, Sturm in pupi- 

 phaga. 



Myxexorista pcxops B. B. is included and stated to have a 

 shortened uterus with slate-gray eggs. It is thus clearly not 

 the genus Myxexorista, which is apparently to be considered 

 synonymous with Zenillia, and I propose for it in this paper 

 the new genus Myxexoristops. Zenillia libatrix has black 

 eggs of smaller size, a long uterus, and more numerous ova- 

 rioles. 



Baumhaucria and Fronthia both fall in the same group with 

 Myxexoristops^ so far as the egg, uterine, and ovarian charac- 

 ters pointed out by Pantel go. They may be found ultimately 



