UNITED STATES DEPARTMENT OF AGRICULTURE 
BULLETIN No. 885 
Contribution from the Bureau of Entomology 
L. O. HOWARD, Chief 
Washington, D. C. 
December 11, 1920 
THE BLACK FLY OF CITRUS AND OTHER SUB- 
TROPICAL PLANTS. 1 
By Harry F. Dietz, Entomological Inspector, Bureau of Entomology, United States 
Department of Agriculture, and James Zetek, Entomologist, The Panama Canal. 2 
CONTENTS. 
Page. 
Introductory ... 1 
The scientific name of the insect and to whom 
it should be accredited 2 
Literature 3 
Origin and distribution 3 
Spread of the insect in the New World. 6 
Food plants 14 
Injury 18 
Life history and habits „ 22 
Eggs 29 
First larval instar 31 
Second larval instar 32 
Third larval instar 33 
Fourth instar, orpupa 34 
Page. 
Life history and habits— Continued. 
Fifthinstar, adult orimago 36 
Technical description 39 
Seasonal history 42 
Parthenogenesis 44 
Natural factors that tend to control the black 
fly in the Canal Zone 44 
Natural enemies 45 
Artificial control 45 
Possibility of the black fly being introduced 
into the United States and factors influ- 
encing its establishment here 47 
Summary 52 
Literature cited 53 
INTRODUCTORY. 
The black fly, Aleurocanthus woglumi Ashby, known also as the 
^ spiny citrus white fly and as the mosca prieta, is a tropical pest of the 
* This work was done in cooperation with the Panama Canal, the second-named author being delegated to 
work with the bureau's representative. To the various departments and divisions of the Panama Canal 
which have aided and cooperated with them the authors are grateful. Special thanks are due the health de- 
partment for providinglaboratory space and facilities for carrying on the work, and the authors are indebted 
to the chief health officers, Col. H. C. Fisher and Lieut. Col. A. T. McCormack, and to the directors of the 
Board of Health laboratories, Drs. Oscar Teague, Wm. L. McFarland, and Lewis B. Bates, for their en- 
couragement and advice from time to time. 
The studies on the life history, habits, hosts, distribution, and control of the black fly in the Canal Zone 
and the adjoining parts of the Republic of Panama were begun in June, 1918, and the authors have been 
assisted in this work by Mr. Ignacio Molino, who, as entomological laboratory assistant, deserves special 
mention for the way he has carried on the work that has been assigned to him. Observations and experi- 
ments made by him are given full credit in the following pages. 
Practically all the published literature relating to Aleurocanthus woglumi has been consulted and the 
data set forth compared with those obtained in the Canal Zone. Unpublished reports on this insect in the 
* files of the Bureau of Entomology have been consulted, and much that was both interesting and helpful 
has been obtained in the discussions that one or both of the authors have had with Mr. J. E. Johnston, of 
the Comision de Sanidad Vegetal de Cuba, and Mr. Harold Morrison and Dr. A. C. Baker, of the Bureau of 
Entomology. Full use has been made of an unpublished report of Mr. Morrison on the status of the black 
fly in the West Indies. 
2 The arrangement of the authors' names is alphabetical and denotes neither seniority nor precedence. 
185528°— 20 1 
