302 KANSAS UNIVERSITY SCIENCE BULLETIN. 



instances of eumenids destroying insects of considerable eco- 

 nomic importance. Representatives of the following families 

 are recorded as being destroyed by eumenids : Lepidoptera — • 

 Notuidse, Pyralidse, Hesperidse, Tortricidse, Geometridse, and 

 CEcophoridse ; Coleoptera — Curculionidje and Scurabidse ; Hy- 

 menoptera — Tenthredinidse. 



The economic insects destroyed by eumenids that are noted 

 in this paper are as follows : Cutworms, destroyed by Monobia 

 quad rid ens, noted by Ashmead ; canker-worms, noted by Harris 

 and the parsnip web-worm (Depressaria hearcliana) , noted by 

 Southwick, both destroyed by Eumeites fraternus; the Larch 

 sawfly [Nematns erichsonii), destroyed by 0. capra, observed 

 by Fyles ; Pempelia gleditschiella, destroyed by a small Ody- 

 nerus, observed by Marlatt; the cotton worm, destroyed by 

 0. dorsalis, obsei-ved by Hartman ; Loxostege stricticalis, de- 

 stroyed by 0. ammlatus, observed by Hungerford and Wil- 

 liams; the same caterpillar, destroyed by 0. arvensis, observed 

 by myself. 



A comparison of four species that I observed indicates that 

 the tube which some species construct over the entrance of 

 their buri'ows is of value in excluding parasites. The observa- 

 tions are too few to serve as anything more than an indication 

 of this. 0. dorsalis, which built no tube, was heavily para- 

 sitized, while O. papagornm, 0. arvensis. and O. annidatus, 

 all tube builders, seemed little troubled with parasites. 



The mo.st persistent parasites of the Eumenidse are in the 

 family Chrysididse. Other families, representatives of which 

 have been found in nests of eumenids, are : Diptera — Bomby- 

 liidpe and Tachinidse ; Hymenoptera — Ichneumanidse, Bracon- 

 idse, Mutilidse, and Myrmicidse. Aptera — robber flies (Asilidse) 

 — may 'also be listed as enemies of the Eumenidae, although 

 they have not been taken in nests of eumenids. 



The purpose of the suspension of the egg from the roof of 

 the cell can not be, for all species, as Fabre suggests, to pre- 

 vent the egg from coming in contact with the writhing larvae. 

 If this is the purpose of the suspensory thread, it is unsuccess- 

 ful in many cases. In the observations of the Peckhams on the 

 nests of 0. anorrms, and in my own observations on four 

 species, 0. papaporum, O. do)'saUs. 0. annidatus and 0. ar- 

 vensis, the egg was found among the caterpillars. Riley refers 

 to Harris as stating that the nest of E. fraternus was packed 



