SERPHOID AND CHALCIDOID PARASITES OF THE HESSIAN FLY 123 



Male.— Length 0.6 to 0.9 mm. Antennal scape greatly enlarged, ovoid, its 

 length to its breadth about in ratio 7:5, pedicel not quite twice as long as 

 broad ; funicle joints a little shorter than in the female, the first funicle joint 

 about as broad as long and not so obliquely truncate at apex ; second joint a 

 little thicker than the first and about one and one half times as long as broad ; 

 third joint about as long as broad at apex; club longer than the funicle and 

 a little thicker than the last funicle joint, curved slightly at apex. Abdomen 

 not longer than the head and thorax, ellipsoidal. Other characters as in the 

 female. 



Described from the type and 20 additional specimens in the 

 National Museum collection. 



REVIEW OF LITERATURE 19 



Girault described Tumidiscapus flavus from one male specimen 

 collected on a window pane at Centralia, 111. This specimen, which 

 is not only the type of the species but of the genus also, is mounted 

 on a slide in the National Museum collection. In 1912 a translation 

 of the original description into Spanish was published by Garcia 

 Mercet without adding anything to the knowledge of the species. 

 The only other reference to it in the literature appears to be one by 

 the writer in 1919, in which an outline figure of the male antenna 

 is given in connection with a discussion of the relationship of the 

 genus Tumidiscapus to Paraphelinus Perkins. 



HOSTS AND LIFE HISTORY 



Tumidiscapus -flavus was first linked with a definite host when, in 

 October 1923, 18 specimens which had been reared June 20, 1923, 

 by W. B. Cartwright from two hessian-fly puparia collected at 

 Union City, Tenn., were identified by the writer as being that species. 

 A specimen reared from a puparium of the same host insect by 

 P. R. Myers in 1915 at Montour sville, Pa., was subsequently identi- 

 fied as T. -flavus. So far as the writer is aware, these two rearings 

 constitute the only records to date of the species from Phytophaga 

 destructor. Two additional specimens in the National Museum col- 

 lection, which have been identified as T. flavus, are said to have been 

 reared from Lasioptera on Muhlenbergia at Elk Point, S.Dak., by 

 C. N. Ainslie, under Webster no. 11838, and three specimens are said 

 to have been reared from Muhlenbergia by the same collector at 

 Sioux City, Iowa, under Sioux City no. 2719. 



Other species of the genus Tumidiscapus seem to be parasitic in the 

 eggs of Orthoptera deposited in stems and canes, and it is highly 

 probable that the normal host of this species will be found to be 

 some orthopteron or other insect that oviposits in grass or weed 

 stems. 



No information is available regarding the life history of the 

 species other than the fact that it emerges from the puparium of 

 its host, as many as 10 specimens sometimes coming from a single 

 puparium of the hessian fly. It is believed to be an internal, pri- 

 mary parasite, but this remains to be proved. 



19 This species was recorded by Metcalf and Colby (Jour. Econ. Ent. 23 : 108, 1930) 

 as parasitic in the eggs of OrcJielimum vulgare Harris, the meadow grasshopper, the iden- 

 tification having been made by the writer. A subsequent reexamination of the parasite 

 material retained showed it to represent a species different from flavus, and it has been 

 recently described under the name of Tumidiscapus orchelimumis (Ann. Ent. Soc. Amer. 

 25: 741, 1932). 



