jiiaes, 1916 Hessian-Fly Parasites 373 



of parthenogenetic progeny has not yet been definitely settled. Mated 

 females produced both male and female progeny. Two mated adults 

 kept separately in vial cages from the time they emerged from pupae 

 until they died each laid a total of 58 eggs. This number actually 

 was found in each case by dissection of flaxseeds which had been exposed 

 to the adult. A few eggs may have been lost in dissection. These 

 adults remained alive for periods of 48 and 56 days and were oviposit- 

 ing during periods of 29 and 46 days, respectively. Another adult, 

 caught in the field while ovipositing in a flaxseed, remained alive in 

 a vial cage and oviposited in flaxseeds during a period of 57 days. An 

 unmated female was kept alive in a vial cage for 83 days. How long 

 adults normally live in the field is not known. 



In one experiment Mr. W. H. Larrimer, of the Eureau of Entomology, 

 exposed stems of Elymus canadensis containing galls of Isosoma sp. to 

 two Eupelmus allynii females which previously had been ovipositing in 

 Hessian-fly puparia. They at once oviposited in the galls. The galls 

 were dissected and the inclosed larvae of Isosoma sp., together with the 

 eggs of E. allynii found in the galls, were transferred to glass-cell cages, 

 one larva of Isosoma sp. and one parasite e^gg to each cell. The para- 

 sites proceeded to complete their development to adults on the larvae 

 of Isosoma sp. Progeny were also bred on the Hessian fly from the same 

 parents used by Mr. Larrimer. These parents and their progeny were all 

 determined by Mr. Gahan as E. allynii. 



MERISUS DESTRUCTOR 

 THE EGG 



The Q.gg of Merisus destructor Say (PI. LI, fig. 5) is elongate, kidney- 

 shaped, circular in cross section, with one end smaller than the other. 

 It is white, wuth the surface apparently smooth. The average length of 

 eggs measured was 0.4 mm., the average diameter at thickest point, o.i 

 mm. Hundreds of the eggs were dissected from flaxseeds, in which they 

 had been deposited, and in all cases they were found external to the host 

 larva or pupa inside the puparium. Some eggs apparently bore a short 

 pedicel on one end, which seemed to be fastened to the inside of the host 

 puparium. Ordinarily, however, the eggs were found free. 



M. destructor, like E. allynii, normally oviposits in the Hessian-fly 

 flaxseed, according to the observations of Mr. Kelly and the author at 

 Wellington, Kans. It was very abundant in the fields at times when 

 no other stage of the Hessian fly was present. The females were 

 repeatedly observed ovipositing in puparia in the field. In cages they 

 also oviposited readily in flaxseeds contained in sections of wheat stems 

 as well as in naked flaxseeds removed from stems. They did not ovi- 

 posit readily in sections of stems containing only partially grown Hessian- 

 fly larvae, although they seemed interested in them. In one instance, 



