18 THE BEAN THKIPS. 
The male. 1 when inclined to copulate, picks out a female, and if 
she is moving over the leaf runs after her and jumps or alights on her 
back. In some cases he then spreads the wings and moves them up 
and down, at the same time moving the tip of the abdomen in the 
same manner. In other cases the male, after leaping onto the back 
of the female, remains motionless for some time in that position. It 
then exserts the copulatory organs from the tip of the abdomen and 
shifts around toward the side of the female, at the same time bend- 
ing the abdomen under to the ventral side of that of the female. The 
copulating organs are then moved back and forth until they en- 
counter those of the female. In some cases observed, when the male 
did not succeed in connection, it would withdraw to its former posi- 
tion on the female and after remaining quiet for a short time would 
move over and attempt the act on the opposite side. As soon as con- 
nection is made the male remains motionless for a short time, during 
which period the female, in many cases, crawls slowly around on 
the leaf. After a few minutes the male relinquishes his hold with 
the copulating organs and moves squarely back onto the dorsum of 
the female. Soon after the male crawls off and away from the female. 
This entire operation was observed in three cases to occupy 3, 5, and 
10 minutes. Several cases were observed where two males attempted 
copulation with the same female, but, after a vain attempt, one 
generally left her. 
METHOD AND TIME OF OVIPOSITION. 
Exactly how much time elapses between copulation and oviposition 
was not observed, but probably not more than a day, so that the 
female will begin oviposition within three days from the time she 
emerges from the pupa. In one case adults emerged on July 19, 
1911, and eggs were laid four davs later. 
Oviposition usually takes place during the night, but has been 
observed at 2, 3, and 4.30 in the afternoon. A female engaged in 
oviposition was observed to crawl over the leaf of the food plant 
for a short distance and then to stop and scrape a hole in the leaf 
with her mouth cone. This was accomplished by a slight forward 
and backward motion like that of a chisel. In a short time the 
female ceased this action and moving forward until she could place 
the tip of the abdomen where the tissue had been ruptured, arched 
the abdomen in the middle, and brought the tip to the opening in 
1 Pietro Buffa (Atti Soc. Toscano Soc. Nat. Mem., vol. 23, p. 48, 1907) figures JEolothrips 
fasciatus, female and male in copulation, in a position identical with that observed by 
the writer in Heliothrips fasciatus on many different occasions. 
A. F. Shull (A Biological Survey of the Sand Dune Region of Saginaw Bay, Mich., 
pp. 190-192), describing copulation in the suborder Terebrantia, expresses doubt as to 
the position of the male on the back of the female during copulation. As his observa- 
tions on Euthrips tritici were made under unfavorable conditions his conclusions were 
probably erroneous. 
