423 



Hill (C. C). U.S. Bur. Ent. A Preliminary Account of Two Serphoid 

 (Proctotrypoid) Parasites of the Hessian Fly. — Proc. Ent. Soc. 

 Washington, D.C., xxiv, no. 5, May 1922, pp. 109-117. 



The Proctotrupids, Platygaster vernalis, Myers, and P. hiemalis, 

 Forbes, which are both important parasites of the Hessian fly, Mayetiola 

 {Phytophaga) destructor, Say, have frequently been confused owing 

 to the similarity in appearance of their adult stages and the lack of 

 information concerning their life-histories. The present preliminary 

 notes are therefore published, pending the completion of more 

 exhaustive investigations. P. vernalis emerges in early spring when 

 the Hessian flies are beginning to oviposit, and deposits eggs singly 

 in the eggs of its host, or in the newly-hatched larvae before they 

 have left the exposed surface of the leaf. The egg of the parasite 

 develops in the mid-intestine of the host, and the primary larvae 

 begin to imbibe the chyle from the host stomach and ingest particles 

 of the stomach wall. When almost the entire contents of the host 

 are consumed, each larva forms a separate cocoon, in which it pupates. 

 The parasitised host larva very seldom succeeds in pupating. Pupation 

 of the parasite usually occurs about the end of July, and by the end of 

 the first week in August the adult stage is probably reached, the autumn 

 and winter being passed in this stage in the cocoons. Occasionally 

 adults emerge in autumn and oviposit in the autumn generation of 

 the host, but field observations indicate that these ovipositions fail 

 to mature. 



P. hiemalis, Forbes, has but one generation in a year, the adults 

 emerging in auturhn when the Hessian flies are laying their eggs for 

 the over-wintering generation. The parasite deposits an average of 

 4-22 eggs at each oviposition in the host egg or young larva. Cold 

 weather greatly retards the development of the growing embryos, and 

 frequently the early summer is passed in the embryonic stage in the 

 body cavity of the host. The larvae soon devour almost the whole 

 body-content. Pupation occurs during July, from 1 to 23 cocoons being 

 found in one puparium, and by the end of August the majority have 

 developed into adults. Weather conditions have a great effect on 

 the seasonal history, and adults occasionally emerge throughout the 

 summer months. 



The characters differentiating the two species in their immature and 

 adult stages are enumerated. 



WicKHAM (H. F.). Weevils of the Genus Apion injurious to Beans 

 in Mexico. — Proc. Ent. Soc. Washington, D.C., xxiv, no. 5, 

 May 1922, pp. 118-122. 



During observations on the Mexican bean beetle [Epilachna cornipta, 

 Muls.] many bean plants were found infested by species of Apion, 

 which ate small holes in the leaves. These weevils occurred on bean 

 plants all round Mexico City, one species being identified as A . grisenm. 

 Smith, and three other species being apparently unknown in Mexico. 

 Infested pods showed yellow or brownish discolorations along the sides, 

 rot frequently setting in from these blotches and breaking down 

 the tissues. The grubs were found to burrow well within the seed 

 while the latter was still soft, but sometimes fed largely from the 

 surface. The larva constructs a pupal case within the bean pod, and 

 the adult emerges by making an irregular opening in the cell. Adults 

 and feeding and other larvae can frequenth^ be found in one pod. The 

 damage in the most carefully examined plot was estimated at about 



