98 MISC. PUBLICATION 17 4, U.S. DEPT. OP AGEICULTURE 



REVIEW OF LITERATURE 



For over a quarter of a century this species was confused in the 

 literature with {Stictonotus) Eridontomerus isosomatis (Riley). Dur- 

 ing that time it was variously referred to as Stictonotus isosomatis, 

 Semiotellus isosomatis, and Merisus isosomatis. In 1920 the present 

 writer pointed out that the supposed type of Stictonotus isosomatis 

 Riley in the National Museum, which had formed the basis for the 

 current conception of that species, was a misidentification and that 

 the real types of Riley's isosomatis represented a species belonging 

 to the monodontomerine genus Eridontomerus Crawford. At the 

 same time the isosomatis of authors (not Riley) was declared to 

 be identical with Merisus febriculosus Girault, the description of 

 which appeared in 1917. 



Apparently the first reference in the literature to this species was 

 that by Webster in 1893, when he recorded the rearing of what he 

 called Merisus isosomatis from wheat stems infested with an uniden- 

 tified species of jointworm. Webster referred to it again as an 

 enemy of jointworms in 1903, 1905, and 1908. In 1909 Webster and 

 Reeves published a figure of the adult female and characterized the 

 species as a very efficient parasite of the wheat jointworm. It was 

 first recorded as a parasite of the hessian fly in 1910 by Kelly, who 

 gave a brief outline of its life history. It was listed as a parasite 

 of Harmolita, tritici in the 1910 edition of Smith's Insects of New 

 Jersey, and again by Viereck in 1916 in his Hymenoptera of Con- 

 necticut. Girault described the species as new under the name of 

 Merisus febriculosus in 1917, using as types specimens from Wooster, 

 Ohio, which were probably reared from jointworm material by Web- 

 ster and, as already stated, this name was applied to the Merisus iso- 

 somatis of authors (not Riley) by the present writer in 1920. Phil- 

 lips and Poos mentioned it in 1923 as a parasite of Harmolita grandis 

 (Riley), and in 1928 Hill and Smith included it in their discussion 

 of the status of hessian-fly parasites in the Middle Atlantic States. 



HOSTS AND LIFE HISTORY 



Merisus febriculosus has been recorded as a parasite of Harmo- 

 lita grandis (Riley), H. tritici (Fitch), H. hordei (Harris), and 

 Phftophaga destructor (Say). Kelly has also stated that it some- 

 times develops as a secondary parasite through Eupelm/ws allynii 

 French and that it is in turn sometimes attacked and destroyed by 

 that species. Myers' unpublished manuscript avers that on one 

 occasion a male specimen was reared from Plati/gaster zosine and 

 that at other times the species was observed to attack the larvae of 

 certain unidentified chalcidoid parasites. 



The life history is not perfectly known, but the species is nor- 

 mally a primary parasite. According to Kelly the egg is deposited 

 in the cell of the Harmolita or in the puparinm of the hessian fly, not 

 always in contact with the host larva, and hatching takes place in 

 3 to 6 days. The larva feeds externally upon the host larva and 

 matures in from G to 15 days. Pupation takes place within the host 

 cell or puparium, as the case may be, and the pupal period requires 

 from 7 to 12 days in the summer time. The winter is passed as a 

 pupa. Only one individual emerges from a single host. Kelly 

 claims to have observed at least two generations per year. 



