168 MOSQUITOES OF NORTH AMERICA 
a number of living Anopheles and Culex larve. The bottom of the bottle was 
literally covered with heads, breathing tubes and decaying parts of the larve 
which these big cannibals had destroyed on the way. There were no plants in 
the bottle. 
“ [T] observed one Psorophora attack another. It seized its victim in the thin 
tissue which unites the breathing tube to the body. With its own breathing tube 
at the surface, it held its victim firmly in spite of its wiggling in its struggle to 
escape, keeping it always below the surface. Of course with its advantageous 
hold it could quite easily keep its victim from getting a fresh supply of air and 
thus it was drowned. I did not see that the victim made any attempt to bite its 
captor, only wiggling violently. After several minutes it seemed to be nearly 
dead, struggling occasionally and the valves at the end of the breathing tube 
could be seen to frequently open and close in the water. When disturbed the 
victor would now swim down with its prey, soon coming to the surface again 
but never once losing its hold. 
“ Another larva came up and proceeded to assist the victor, eating off all the 
anal flaps of the victim. When disturbed again the second one let go but the 
first one held on and was taken out in a watchglass, nearly all the water removed 
therefrom, and examined under a compound microscope. It still held to the 
same place, the mandibles working far into the mouth and carrying the tissues 
with it but without appearing to masticate them. It was apparently sucking 
the juices from the victim which was shrinking in size. 
“ Another Psorophora was observed to take a 3/4 grown Culex larva by the 
head and swallow it whole as a snake does a frog. The whole operation did not 
take more than half a minute. 
“The mouthparts are rarely moved except when attacking prey. Yesterday I 
saw one Psorophora seize a piece of water plant and bite enough to pull it along 
with it. 
“T divided the Psorophora larve into three lots of 16 each in evaporating 
dishes and from a bucket of standing water back of insectary, I procured a large 
number of Culex larve which I put into the Psorophora dishes. Immediately 
they seized upon the Culex and 8 or 10 at one time had Culex larve part way 
down. In only one case out of many (probably 40-50) did I see a Culesx seized 
tail first. It took from 2 to 3 minutes to swallow the largest Culea larve and 
from that to perhaps 20 seconds for very small ones. 
“The method of catching is as follows: The Culex hang at the surface head 
downward while breathing. Sometimes the Psorophora floats along in similar 
position toward it, sometimes remains motionless till Culea comes within reach. 
When they have reached a position so that Culex hangs almost directly over 
the head of Psorophora, like a flash, before Culea has time to move, the Psoro- 
phora turns its head (its mouth is on under side) and seizes Culex by the head 
in a fatal grasp, pulling it under and, in spite of its victim’s struggles, quickly 
swallowing it whole. 
“T examined some excrement just as it came from one larva and found that 
it was composed of the breathing tube and the two main tracheal tubes from the 
body of the victim passed whole through the alimentary canal of the cannibal. 
From these observations on eating whole larve it may be inferred that practically 
all the heads and breathing tubes which strew the bottom of my jars by hun- 
dreds, yes thousands, have passed through the alimentary canals of the Psoro- 
phora larve. 
“In the case of the Psorophora eating each other, the strongly chitinized 
breathing tubes and the cylinder around the last segment are rejected as too 
tough, but in the case previously observed this day fully 1/2 the length of the 
body posteriorly has been thoroughly chewed up and the inner soft parts ab- 
