ACKNOWLEDGMENTS 
Preparation of this manual has been 
possible as a result of a USDA Coopera- 
tive Agreement made through the active 
support and interest of R. H. Hodges, 
formerly Chief, Systematic Entomology 
Laboratory, U.S. Department of Agri- 
culture. R. J. Gagn£, lead scientist 
of the Diptera Unit of the Systematic 
Entomology Laboratory, has given 
advice and assistance throughout the 
preparation of the publication. Sin- 
cere thanks are due both Dr. Hodges 
and Dr. Gagnd. 
We are grateful to the authorities of 
the Smithsonian Institution for facili- 
ties to study types. Types and other 
material have unhesitatingly been lent 
by the following institutions: Bio- 
systematics Research Institute, 
Agriculture Canada, Ottawa; British 
Museum (Natural History), London; 
California Academy of Sciences, San 
Francisco; Cornell University, Ithaca, 
N.Y. ; Illinois Natural History Survey, 
Urbana; Iowa State University, Ames; 
Museum of Comparative Zoology, Harvard 
University, Cambridge, Mass.; Natur- 
historisches Museum, Vienna, Austria; 
Naturhistoriska Riksmuseet, Stockholm, 
Sweden; Oregon State University, 
Corvallis; Pennsylvania State Universi- 
ty, University Park; Rijksmuseum van 
Natuurlijke Historie, Leiden, Nether- 
lands; Utah State University, Logan; 
and Zoological Institute, Lund, Sweden. 
To the curators of the collections of 
these institutions we express our grat- 
itude for their helpful cooperation. 
individuals for substantial assistance 
in many ways, without which this publi 
cation could not have been completed: 
The senior author’s wife Ann, who made 
most of the drawings; Daphne Allen, 
Plymouth, England; K. E. Frick, 
Southern Weed Science Laboratory, U.S. 
Department of Agriculture, Stoneville, 
Miss.; G. C. D. Griffiths, University 
of Alberta, Edmonton; S. Tavormina, 
University of Texas, Austin; and K. R. 
Valley, Pennsylvania Department of 
Agriculture, Harrisburg. The direct 
experience of these persons with live 
Agromyzidae has enabled them to 
contribute in a very real sense to the 
scientific value of this publication. 
It is inevitable that two systematic 
entomologists have some differences of 
opinion. This manual has been left 
substantially as the senior author 
wrote it, mainly for consistency with 
his numerous other works. 
The outstanding point of difference 
pertains to the rank of supraspecif ic 
taxa. The junior author believes that 
recent workers in Agromyzidae have 
recognized too many taxa as of full 
generic rank. This is especially true 
of Chromatomyia , inasmuch as there is 
nothing unscientific in requiring that 
genera be recognizable by characters 
that apply to both sexes. 
However, a work of this nature is not 
one in which to propose any major 
change in supraspecif ic classification 
iii 
We are also grateful to the following 
