4 A N N UAL REPORT- OK DKIWKTM KNT OF A(1KI< T* LTV RE, 1940 
8,807 prints and negatives. The duplicating work included gen- 
eral Bureau mimeographing, quarantine and administrative instruc- 
tions, and Bureau of Entomology and Plant Quarantine circulars. 
Thirty-five mailing li^ts were maintained in this division. 
To the file of photographic prints under the custody of this divi- 
sion were added •"><*>!> new subjects. A total of 1,319 print- were 
distributed, on special request, to scientific worker-, magazine editors, 
writer-, students, teachers, and other-. 
A new service inaugurated was the collection of all stages of 
ll» different speeies of economically important insects, to comply 
with requests from schools, museums, and other educational insti- 
tutions for actual insect specimens. Although this service i- still 
practically unknown to the genera] public, 194 specimens were dis- 
tributed to meet requests. 
FRUIT INSECT INVESTIGATIONS 
APPLK AM) PEAR INSE< TS 
A study of Comstock's mealybug {Pseiulo coccus comstocki 
(Kuw.)) was undertaken at a new laboratory, established at Char- 
lottesville. Va. The chief damage caused by this mealybug results 
from its profuse production of honeydew, which cover.- the twigs, 
leaves, and fruit. This honeydew supports the growth of a sooty 
mold, or fungus, which stunts the fruit and causes it to color poorly. 
The. insect has been reported with increasing frequency -ince 1W4 
from numerous orchards from South Carolina to Ohio and Connec- 
ticut. Since thus far the ttse of insecticides against this insect has 
not been successful, special attention is being given to biological 
control. In 1938 arrangements were made to bring in from Japan 
certain parasites known to be important in the natural control of 
tin- insect in the Orient. Two of these, both of the genu- AUotropa^ 
were placed in heavily infested orchards in Virginia, West Virginia, 
and Ohio. A parasite species, Clausenia purpurea I-hii. already 
present in certain of the Eastern States, is being recolonized in 
Ohio, from which it has apparently been absent. Experiments are 
also under way with the mass liberation of the ladybird beetle 
( ' r>/ ptohicmus mo/tfrottzieri Muls., stocks of which were obtained 
from ( lalifornia. 
The search for a substitute for lead arsenate tor control of the 
codling moth was continued. Approximately 260 new compounds 
were given laboratory testing, chiefly at Beltsville, Md. These in- 
cluded synthetic organic material- as well as plant extracts. Most 
of the compounds showed little or no toxicity; a few. including 
extracts of the so -called thunder-god vine, seem worth Further testing. 
Work at Beltsville indicated that, under the laboratory technique 
followed there, the addit ion of certain -weet materials to lead arsenate. 
calcium arsenate, nicotine bentonite, and phenthiazine materially 
increased the mortality resulting from their use. This, however, has 
not been confirmed under orchard conditions. 
A number of variations of the tank-mix nicotine bentonite formula 
were (jested at Vincennes, End., by the field-laboratory method, but 
no improvement was found over the formula looked upon as standard 
for several years. The tank-mix nicotine bentonite continued to give 
