1912 ENTOMOLOGICAL SOCIETY. 71 



The next source of high mortality seemed to be in the imago state^, as num- 

 bers of separate wings of the moths have been found lying on the ground, sugges- 

 .tive of the work of bats; night hawks have also been seen flying about the swamps, 

 but neither bat nor bird has been caught in the act of gobbling a Hepialus. Two 

 years ago we found that many of the wings lying about the. bushes were quite 

 soft and not fully expanded, showing the moths had been devoured between 5.30 

 and 7 p.m., while they were drying their wings preparatory to their first flight, 

 and some small animal is doubtless well supplied with dainties for the few days 

 annually that the moth flies. In our digging operations a few larvge and pupoe 

 were found attacked by a fungous disease — a species of Cordyceps, specimens of 

 which were exhibited at our 1909 annual meeting, but till this year no insect para- 

 site has been met with, nor do I know of any record of a parasite of any North 

 American species. 



On June 23rd, Prof. Swaine and myself spent a couple of hours in a swamp 

 at St. Anne de Bellevue, digging among the willows, resulting in our finding a good 

 many larvge and a few pupae. Owing to our not having all the necessary imple- 

 ments with us we managed to chop in half a great many more of both than we 

 secured intact. Two pupae that I kept looked particularly healthy, and were kept 

 in a roomy cage with plenty of leaf mould and moths were looked for with a 

 degree of certainty. The larvae were put in a tin box filled with the leaf mould 

 and were only taken home for inflation for cabinet specimens, as they evidently 

 would not produce moths till 1912, and no attention was paid to them. Early in 

 July I opened the box, expecting to find the larvae shrivelled up and dead, but 

 instead found the mass healthy and active as ever. The cage with the pupae was 

 looked at daily, but no moths appeared, and although still flexible at the joints it 

 became evident that it was too late for them to produce moths this year. The 

 larvae continued to prosper on their starvation diet, and on July 14th, as I was 

 leaving town for my holidays the following day, I sent the larvae and one pupa to 

 Mr. H. Dawson, Hymers, Ont., to whom I am indebted for much information and 

 many specimens from that locality, telling him that the pupa apparently would 

 not live, and the larvae on the contrary refused to die. The larvae lived till August, 

 some five weeks, without a bite of willow wood, and the pupa produced a fine 

 Ichneumon which Mr. Gibson has kindly had identified by Mr. W. H. Harrington 

 as 7. decinctor Say. My pupa also produced an Ichneumon during my absence but 

 escaped in some way. So we now Icnow that there is at least one Hymen opterous 

 parasite, and are confronted with the question of how does it manage to get .at 

 the larva to attack it? Two methods seem possible; first, by stinging the larva 

 when it is engaged in cutting the exit hole for the moth to escape through, or 

 second, by finding the freshly cut hole and entering bodily and following the tun- 

 nel down to where the mature larva or freshly formed pupa is. Another species 

 of Ichneumon. I. subdolus, has been found to be parasitic on a bormg moth larva, 

 Gortyna immanis, but the stems of the hop vine do not seem as secure a hiding 

 place as the roots of the willow. 



While it is often a great disappointment to a collector who has spent time 

 feeding and caring for larvae to have them produce Ichneumons or other parasites 

 instead of moths, one is often compensated by the fine condition the pupae or chrys- 

 alids are left in for cabinet specimens, besides what is learned of the relationships 

 between the destroyer and the destroyed. As well as the pupa of Hepialus thule 

 you will notice in the box a chrysalis of Papilio asierins. In both cases the parasite 

 escaped through neat holes in the sides instead of bursting the shell completely as 

 the moths and butterflies do in the natural course of events. 



