THE BLACK FLY OF CITRUS. 49 
Remarks: 
June 9 — Two females and two males emerged. All in the morning . 
June 10 — One female and one male emerged. Both in the morning. 
June 11 — No emergence; leaf thoroughly dry. 
June 12 — One female emerging. T-shaped slip on pupa visible, but 
individual having trouble, due to dry conditions. Moisture added 
to petri dish. 
June 13 — One female of June 12 died in emergence. T-shaped slit 
slightly spread open, indicating feeble attempt of individual to 
June 14 to 20 — No further emergence. Pupae all dead on examination. 
Experiment discontinued. 
EXPERIMENT NO. 5. 
Number of pupse — 87 females and 18 males, from which 3 females and 2 males 
had emerged before these were brought to the laboratory 
on June 5, 1919, and were put in a petri dish. 
Remarks: 
June 5 to 9 — No emergence. Leaves very dry on June 9. 
June 10 — One male emerged in morning. 
June 11— No emergence. 
June 12 — One female emerging in morning. Moisture added. 
June 13 — Female emerging June 12 died in process. 
June 14 to 20 — All pupae dead on examination June 20. Experiment 
discontinued. 
The third of the methods outlined, namely, the bringing in of eggs 
on the fruits, seems to be a rather remote one. That the adults do lay 
eggs on the fruits under certain conditions has been demonstrated by 
Morrison (1917) and by the writers, and though the writers have failed 
to find this the case out of doors in the region where they have worked, 
they fully realize that it may take place. But the first-instar larvae of 
A. woglumi are not like the larvae of scale insects, as has been shown 
under the heading "Life history," p. 31. They are sluggish crawlers 
and have little ambition to wander far from the eggs from which they 
have hatched. Hence, even if the eggs on fruit would hatch the larvae 
would either settle down on it or, if they fell off, would perish. The 
following experiment shows how remote the possibility of the insect 
being introduced in the egg stage and becoming successfully estab- 
lished really is. 
In order to see if larvae would migrate far the following experiment 
was tried: Two leaves bearing about 200 eggs each, from which larvae 
were just beginning to hatch, were removed from a twig and tied to 
two leaves on a young tree in the laboratory. One was tied so that 
parts of its under surface rested against the under surface of the leaf 
on the tree and the other was tied so that its under surface rested 
against the upper surface of the leaf on the tree. Five days later, 
when the leaves bearing the eggs had completely dried out, an exami- 
nation was made, and it was found that only four larvae had crawled 
185528°— 20 1 
