ENTOMOLOGICAL SOCIETY OF ONTARIO. 51 



delidoa) fig 47, also prey upon them. Bat, probably, one of the greatest insect friends 

 to assist in destroying the army worm is the red tailed tachina fly (Nemorcea leucanice) fig, 

 50. In the infested fields of Wainfleet near Marshville, the writer found many of the 

 caterpillars, bearing the eggs of this insect upon them. In some cases, several eggs upon 

 a caterpillar, and the flies themselves buzzing around. At the college we seldom saw 

 more than a single egg upon a caterpillar and this was usually near the head, in a posi- 

 tion not easily reached by the worm to tear it off. We succeeded in developing quite a 

 number of the flies. Shortly after the egg is deposited it hatches, and the small white 

 grub bores into the worm (host) and feeds upon it, developing at the expense of the host's 

 life. At first, none of the minute white eggs of the fly could be seen, though many 

 caterpillars were examined, but in a few days, some were observed which indicated that 

 a benefactor had arrived. This beneficial insect resembles a large house fly, but has a 

 red tip at the end of the body. The first one appeared in our breeding cages Aug. 4th ; 

 the first army worm moth July 29 ,h. Some observers have seen the yellow- tailed tachina 

 fly (Tachina Jlavicauda) preying upon the army worm. 



While developing the caterpillars we succeeded in securing several specimens of 

 Ichneumon leucanice, another parasite, and one of Oyhion purgalus. 



Altogether, investigators have found some twenty different species of insects that 

 attack and assist greatly in destroying the army worm. 



It will thus be seen that the moment these insects emerge from their hiding places 

 in grass fields, they are pursued by a host of relentless foes in the form of birds, pre- 

 daceous beetles and parasitic flies. 



Artificial remedies. 1. As this insect breeds largely in rank grass, such as is seen 

 bordering swamps, it is well, where practicable, to burn such in the fall or spring. Clean 

 cultivation, and the keeping of fence corners, etc., clean, should be followed, as far as 

 possible. 



2. Where the worm has appeared its progress may be stopped by plowing a furrow 

 with its p^rp-ndicular side next, the field to be protected, or a ditch may be dug in the 

 same position. Holes dug at intervals of ten to fi'teen feet, in the furrow or ditch will 

 be useful in catching the worms, failing to climb the sides, and wandering aimlessly 

 along the furrow. The worms collected in the furrow or ditch may be des royed as fol- 

 lows : (a) Plowing a furrow, so as to bury them ; (h) Sprinkling coal oil upon them ; (c) 

 Scattering straw over them and firing it ; (d) Dragging a heavy pole along the ditch. 



3. Where Paris green may be safely used a strong mixture (one pound to seventy- 

 five gallons water) sprayed upon the plants likely to be first attacked will be effective. 

 Windrows of grefn oats sprinkled in this way in the line of march will destroy myriads 

 as they feed upon their favorite food. At ihe College immense numbers were destroyed 

 in this way in a short time. By actual count made by the writer July 18th, 2,560 dead ' 

 worms lay on a single square foot beneath the windrows. 



4. Sometimes, conditions are such, that great numbers may be crushed under a 

 roller. 



5. Windrows of straw sometimes afford a plaee of concealment for the worms, and 

 may be fired so as to destroy many beneath them. 



6. Some recommend spraying several times a day with kerosene emulsion, a strip of 

 ground over which the insects are passing. 



Fr< qnent reference has been made in newspapers to the use of salt or lime as an 

 effectual harrier to their progress. We experimented with both, and found that iu each 

 case the worms moved over and through the lime and salt, apparently without the least 

 difficulty. 



