Junes. i9t6 Hessian-Fly Parasites ^'j'j 



to her and later dissected. Some may have been lost in dissection. This 

 female was laying eggs during a period of six weeks. Other females were 

 kept alive and active in confinement for periods of over two months. 



Some stems of Elymus canadensis containing galls formed by a species 

 of Isosoma were placed in a vial cage containing females of M. destrtcctor. 

 Almost immediately one of the females became interested in the galls, 

 feeling over them with her antennae. She then attempted to oviposit, 

 endeavoring persistently to penetrate the gall with her ovipositor, but 

 without success. Mr. W. H. Larrimer finally succeeded in getting the 

 females to oviposit in the Isosoma galls and found the eggs inside the 

 galls but external to the larvas of Isosoma sp. He actually reared a few 

 specimens of M. destructor from egg to adult on the Isosoma larvae in glass 

 cells. The parents used in this experiment and the progeny which were 

 reared were determined as Merisus destructor by Mr. Gahan. 



MICROMELUS SUBAPTERUS 



Heretofore it has been uncertain that the winged and wingless forms 

 of Micromelus suhaptcrus Riley were the same species. It has been 

 proved, however, that the two forms are specifically identical by breeding 

 a wingless female from a winged parent. Further evidence indicating 

 that the winged and wingless forms are the same species is the fact that 

 wingless males mated with winged females as readily as with the wing- 

 less form. The method by which the wingless female was bred from the 

 winged parent is as follows: The winged parent deposited an egg in a 

 Hessian-fly puparium known to have been previously unparasitized. The 

 t.gg was removed from the puparium and from it a wingless adult was 

 reared on a healthy Hessian-fly larva, which also had been dissected from 

 its puparium. Mr. Gahan found this wingless offspring of a winged adult 

 to be identical with winged specimens of unknown parentage. 



THE EGG 



The egg of Micromelus subapterus (PI. LI, fig. 7) resembles that of Merisus 

 destructor in size and shape. It is elongate, kidney-shaped, with one end 

 longer than the other, circular in cross section, white in color, with sur- 

 face of shell smooth, and about 0.38 mm. long by 0.09 mm. in diameter 

 at the thickest point. It has no stalk. 



All the observations made at the Wellington (Kans.) station lead to 

 the conclusion that the egg is normally laid in the Hessian-fly puparium. 

 In cages the adults oviposit readily in flaxseeds, the eggs being placed 

 inside the puparia but external to the inclosed Hessian-fly larvae and 

 unattached. This was the case both when stems of fly-infested wheat 



1 Mr. A. B. Gahan makes the following statement: " The real generic position of this species is in doubt. 

 It was originally described by Riley under the name Merisus (Ilomoporus) subapterus Riley, and later 

 referred to Boeotomus by Osborn and other writers. N. V. Kurdiumov has more recently placed the 

 species in the genus Micromelus. Doctor Ashmead reduced Boeotomus to synonymy with Micromelus." 



• 37767°— 16 4 



