1924 ] 
Biological Notes on Lethocerus americanus 
177 
in the digestive tract. The second tadpole was then offered to 
the bug with the same result. I was curious to know how much 
more it might eat but refrained from offering more food as I still 
had a vivid recollection of what happened to a number of Ranatra 
that were allowed to gorge themselves. These bugs had had no 
food for several weeks and then one evening offered all the flies 
they could eat. The next morning eleven of the thirteen water 
scorpions were dead. It was at first thought there might have 
been something toxic about the flies and later the experiment 
was tried again. This resulted in the death of all five bugs used 
in the test. Still later the same experiment was tried again, 
this time using cockroaches and damsel-fly nymphs. Again all 
the bugs died. This food ordinarily is very fine for these bugs 
so evidently it was the effect of a large amount of food being 
taken after a fast which caused death. When they have been 
fed more regularly no evil effect seems to occur, even though 
they have all they can possibly consume. 
On the thirteenth of July a move was made to the State 
Fish Hatchery at St. Peter, where some lake studies were to be 
conducted. Some anxiety was felt about successfully trans- 
porting the Lethocerus nymph, but it made the trip apparently 
none the worse for the experience. The trip was made by Ford, 
and this insect along with nymphs and adults of more than a 
dozen species of waterbugs, came through without mishap. The 
distance was only eighty-five miles but the life histories were 
^ ^packed up” for about fifteen hours. Before packing for the 
trip the water was drained from the life history jars, leaving the 
bugs upon the wet sand. 
In its new home the Belostomid was fed mostly on young 
trout. Two inch trout were given every other day, with an 
occasional feed of grasshoppers, crickets and flies. It was fed 
trout principally, because the laboratory was located in a trout 
hatchery and trout became the most available food source. 
Every day the vegetation near the hatchery was “swept” for 
soft-bodied insects which were used as food for Velia, Microvelia, 
Gerrids, Nepa, Ranatra and other bugs in rearing. Grasshoppers 
and other large insects were often taken inadvertently and ac- 
cordingly were given to the Lethocerus. The bug would refuse 
