390 



JOURNAL OF ECONO^IIC ENTOMOLOGY 



[Vol. 8 



to find them. As they have the same habits as the cutworms they 

 should have about the same parasites. 



Because of the necessitj^ of hiding themselves during the daytime, 

 the larvae prefer rank-growing crops like broadcast sorghum, sugar- 

 cane, and small grain or hay crops. In these crops they can hide them- 

 selves in the dead leaves on the ground. 



The moths usually lay their eggs between two dead, dry leaves, the 

 eggs being cemented to the leaves. They are apparently well pro- 

 tected from the attacks of parasites. These facts are based on 

 laboratory observations as we have not found the eggs outdoors. 



In rearing the insects in the laboratory the moths are placed in 

 large No. 2 street-lamp globes and are fed on sugar syrup. Folded 

 strips of wrapping paper are placed in the cages for them to lay their 

 eggs on. They lay their eggs freely on this paper and it is easy to 

 handle and always obtainable. 



Larvae are kept in 1-ounce seamless tin boxes, one larva in each 

 box, and are fed on corn leaves if available, otherwise they may be 

 fed on sorghum, oat or barley leaves. Larvae in the first three stages 

 may be kept in 2-, 3-, or 4-ounce tin boxes, many larvae in each box. 



The species all appear to be of tropical or of subtropical origin, 

 and were probably native on rank-growing grasses in lowlands. They 

 spend the winter in all four stages, but as all stages are unprotected 

 against extremes of temperature, it would seem that they cannot 

 winter very far north. It is probable that they usually do not winter 

 very far from the Gulf of Mexico, but in the Mississippi Valley H. 

 unipunda might winter as far north as Tallulah, La., and on the 

 Atlantic coast it might go through a mild winter as far north as the 

 city of Washington. A discussion of the question as to which stage 

 is best able to withstand cold weather is useless speculation as these 

 facts can easily be learned by a series of experiments with low temper- 

 ature incubators. If it should happen at any time that the conditions 

 in the country near the Gulf of Mexico are especially unfavorable for 

 the parasites, the moths would occur in large numbers and migrate 

 northward. In a northern locality the w^orms would be free from their 

 ordinary parasites and would find plenty of food in the grain fields. 

 The young larvae, not being controlled by their parasites, could mature 

 in such large numbers that they would be compelled to migrate in 

 search of food. But this migration would attract predaceous mammals, 

 birds, and insects, and also native parasitic insects normally infesting 

 other lepidopterous larvae. This appears to be what actually occurs 

 in the case of H. unipunda and outbreaks in the north are abnormal, 

 since the larvae are killed by the cold weather and for this reason 

 do not appear the following year. Heliophila suhpundata will perhaps 



