WALNUT HUSK-MAGGOT. 
Creek, W. Va., the first flies appeared in rearing jars on July 16, 
and on August 5 the first specimens were recognized definitely on 
the trees. Flies, apparently of this species, were seen on trees in both 
West Virginia and Pennsylvania several weeks earlier, but no 
specimens were captured and identification was not definite. Flies 
in rearing jars issued from July 16 to September 8, emergence cover- 
ing a period of 55 days. Table I shows the time of emergence of 40 
individuals in rearing jars. 
Table I. — Emergence of flies of walnut hush-maggot in rearing jars at 
French Creek, W. Va., in 1920 
Date 
Num- 
ber of 
flies. 
Date. 
Num- 
ber of 
flies. 
Date. 
Num- 
ber of 
flies. 
Date. 
Num- 
ber of 
flies. 
July 16. . . . 
17.... 
18.... 
19. . . . 
20.... 
21.... 
22. . . . 
23.... 
24. . . . 
25. . . . 
26.... 
27. . . . 
28.... 
29.... 
30.... 
1 


2 

1 

1 


1 




July 31.... 
Aug. 1 
2 
3.... 
4.... 
5 
6.... 
7 
8.... 
9.... 
10.... 
11.... 
12.... 
13.... 
14.... 
1 
1 


1 

1 
1 
1 
1 


I 

Aug. 15... 
16... 
17... 
18... 
19... 
20... 
21... 
22... 
23... 
24... 
25... 
26... 
27... 
28... 
3 

2 
2 
3 



1 
1 
4 
4 
1 

Aug. 29... 
30... 
31... 
Sept. 1.... 
2 
4.... 
'&'.'.'.'. 
7.... 
8.... 
9.... 
Total. . 


1 



1 



1 

40 
Apparently flies are present on the trees several weeks before ovi- 
position begins. At first they occupy the foliage chiefly, making 
short flights from leaf to leaf and resting quietly for long periods. 
During the preoviposition period, as well as later, they may be seen 
lapping at the leaves as though extracting food from deposits on the 
surface. As the time for the beginning of oviposition approaches 
the flies become more active, and both males and females show a 
tendency to gather about the nuts. The males habitually select cer- 
tain nuts on which an individual will take his stand and often remain 
for hours at a time awaiting the coming of the female, combating, 
meantime, other males that approach. When a male alights on a nut 
already tenanted by another male the original occupant attacks it and 
usually the two rear up on their hind legs, facing each other, and en- 
gage in a brief but animated bout, belaboring each other with their 
forelegs. Usually the original occupant is the victor and the would- 
be interloper flies away. 
A prick made in a walnut with a pin or other sharp point was sure 
to be found by a male, who, recognizing it evidently as a suitable 
place for the females to come to oviposit, would immediately begin 
standing guard over it. In one instance the waiter pricked a dozen 
walnuts on the lower branches of a tree with the point of a small 
nail. Thereafter for several days a male was on guardat each of the 
