52 
The main function of the Diptera in the interesting struggle which 
we have described was that of scavengers. The scavenger flies were 
much more abundant than the parasitic flies, and the dead bodies of the 
caterpillars, the chrysalis skins, and the remains of the different species 
of parasites were abundantly preyed upon by species of this class. 
The table which follows shows the exact host relations of the Hymen- 
optera reared in the course of the observations: 
Table showing host relations of the Hymenopterous parasites so far as they are known 
or surmised. 7 
[ Host, Orgyia leucostigma. | 
Possible quater- 
Primary parasite. Secondary parasite. Tertiary parasite. yes 
| 
Pimpla inquisitor.......--. Dibrachys boucheanus ....-.-- Asecodes albitarsis- -. 
| Allocota thyridopterigis.----- Habrocytus thyr.?.... 
| Heripe Dimpleeesee----ee | Dibrachys boucheanus 
| Adiastola americana.....-.-... 
Pimpla annulipes.......--- 
Pimpla conquisitor .......-. | Allocota thyridopterigis.-.---. Habrocytus thyr.?....) 
Ichneumon ceeruleus ..---.) | 
Ichneumon subeyaneus....| | 
Amorphotaorgyl .. ..---.| Spilochaleis debilis ....-. ---. Dibrachys bouchea- | Asecodes albiter- 
nus? | sis? 
| Dibrachys boucheanus ....---| Asecodes albitarsis. .. 
Meteorus communis -...-.- | Spilochaleis debilis..-.....--- | 
Otacustes periliti ............ | 
| Bathythrix meteori.....-..-.-- | | 
Dibrachys boucheanus ....--- | 
Meteorus hyphantrie ..--. Spilochalcis debilis -........-. | Eupelmus limneriz .-. -| 
Otacustes periliti ..-......... | 
| Dibrachys boucheanus .....-. | | 
PiMNeria Spiess eee = = =H 
Limneria valida ..........- Dibrachys boucheanus -..---- | Tetrastichus sp.? ....| 
Eupelmus limneriw..-.....--- 
Elasmus atratus.............- 
Theronia fulvescens......- | 
Apanteles hyphantriw ....; Spilochaleis debilis -.......--- | Dibrachys bouch.? .... Asecodes albitar- 
| sis? 
| Dibrachys boucheanus ....-.-.. Asecodes albitarsis?.. 
Hlasmus atratuS ......-..-...- 
Apanteles delicatus -.....- Spilochalcis debilis ..........- 
Dibrachys boucheanus ...-... } 
Elasmus atratus........-..... 
Chaleis ovata.........----- 
Pteromalus cuproideus - -.-! 
Cratotechus orgyiw.....--. | Elachistus caceecie........-.. 
TPetrastichus sp... 5. s-.-- 5. 
Telenomus orgyil..-.-...-. 
As far as we were able to ascertain, the dipterous parasites had no 
hyperparasites. It will be seen that there were seventeen species of 
primary Hymenoptera and six of primary Diptera. Of the secondary 
hymenopterous parasites there were thirteen species, several of them, 
however, affecting more than one species of primary parasite. There 
were but two species of tertiary parasite, so far as positive observations 
go, but three other species were strongly suspected to sustain this rela- 
tion, while, as indicated, one of the species of which we have proof of 
tertiary parasitism may under certain conditions, in our opinion, prove 
to be a quaternary parasite. In the table those species followed by an 
interrogation point are problematically placed. The parasitism indi- 
cated is strongly suspected, but has not been definitely proved. The 
placing of all of the other species is based upon exact observations. 
