IV. SOME FLY-CATCHERS. 
(a.) Monedula Carolina, Drury, The Big Fly Catcher. 
Monedula Carolina is our largest digger-wasp with the exception 
of Ammophila procera. But the caterpillar-wasp looks comparatively 
weak, being slender, while the big fly-catcher has a most formidable 
appearance on account of her bulk and the warning yellow stripes 
of her abdomen. In the hot months of the year the wasp is often 
met with in search of prey or digging hei nest in the sand, where she 
cuts a conspicuous figure. You cannot proceed far through the 
woods before one of the big fellows will come flying toward you 
with the loud threatening buzz of a bumble-bee. The wasp will fly 
around you to examine you on all sides, keeping her face turned to- 
ward you and as you advance, she will advance with you flying back- 
ward before you. This backward flight of Monedula, almost unique 
among insects, recalls the habit of the South African wasp, cited 
by the Peckhams, which is said to fly backward before a moving 
horse and catch the flies hovering over it. On the authority of a 
friend of mine, I can say the same for Monedula, which often fol- 
lowed his ox-team, picked off the flies and “buried” them in the 
ground. I have myself seen as many as three carolinas around a 
horse or cow at the same time- and there can be no doubt that they 
do not hover around for curiosity’s sake merely. 
M. Carolina spends three or four days digging her nest. The first 
two days she applies herself assiduously for hours at a time and will 
scrape out an astonishing pile of sand. Her working hours are, 
however, extremely irregular, especially on the third and fourth 
days. She may return to her nest at any time of the day, taking 
an hour or two for recreation in the midst of her work. I have seen 
her begin her nest in the morning before any digger-wasp was astir, 
work several hours with diligence and then close the nest and fly 
away, perhaps not to return again for work until late the next 
afternoon after Bomb ex tex. had retired or was playing hide and 
seek among the nests of her colony. Carolina is, moreover, least 
susceptible to the influences of the weather ; for, while other digger- 
wasps will lie listlessly about on a cloudy day or sip nectar from the 
flowers, she may be as busy as ever. 
Like the La Plata species, Monedula punctata , Monedula Carolina 
lays a single egg in the empty nest and waits for the larva to hatch 
before she begins to lay in a supply of flies. This explains her 
