32 MISC. PUBLICATION 174. U.S. DEPT. OF AGRICULTURE 



REVIEW OF LITERATURE 



Specimens reared by C. M. Packard from puparia of the hessian fly 

 at Altamont, Calif., in 1917, formed the basis for the description by 

 the writer, in 1919, of Pseuderimerus mayetiolae. Both the genus 

 and the species were found to be new to science. Subsequently Pack- 

 ard reared many additional specimens of the species. In 1928 he 

 published a bulletin dealing with the host insect in California, in 

 which he made brief reference to this and other parasites. 



HOSTS AND LIFE HISTORY 



So far as known this species has been reared from Phytophaga 

 destructor only. Since it is not known to occur in other parts of the 

 world, it may be assumed to be a native of the Pacific coast region, 

 and as such it must have had some other host before the advent of the 

 hessian fly into that region. Doubtless it will eventually be found 

 to attack some native insect enemy of a native grass. 



It is believed to be a solitary, primary parasite feeding externally 

 upon the larva or pupa within the puparium and emerging as an 

 adult from the fly puparium. 



DISTRIBUTION 



The only specimens of this species thus far seen have come from 

 the following localities in California : Altamont, Birds Landing, 

 Concord, Rio Vista, Benicia, Vallejo, Tres Pinos, and Cordelia. It 

 apparently does not occur in Oregon or Washington. 



IMPORTANCE 



According to Packard, Pseuderimerus mayetiolae is by far the 

 most important parasite of the hessian fly in California, being more 

 widely distributed throughout the fly-infested area in that State and 

 generally more numerous than any of the other parasites. 



PSEUDERIMERUS FEMORATUS, new species 



Pseuderimerus femoratus is very similar to P. mayetiolae but differs 

 especially by having a longer ovipositor, a less strongly sculptured 

 propodeum, and all the femora concolorous with the thorax. The fol- 

 lowing description should serve to distinguish it from mayetiolae. 



Female. — Length 1.8 mm. Scutellum a little shorter than mesoscutum, ap- 

 parently a little more convex and appearing distinctly a little longer than broad ; 

 propodeum weakly reticulated, shining, nearly smooth, distinctly less strongly 

 sculptured than in mayetiolae, without trace of median carina or lateral folds ; 

 anterior and posterior femora very slightly thickened ; first and second tergites 

 weakly emarginate apically ; third and following apparently without emargina- 

 tion ; ovipositor exserted fully one third the length of abdomen. Reticulate 

 sculpture of mesoscutum and scutellum similar to that of mayetiolae but appar- 

 ently not quite so strong. Color nearly black with a distinct tinge of greenish 

 on head and thorax, not at all bronzy ; wings completely hyaline ; venation 

 brown ; all coxae and the femora, except at apices, concolorous with thorax ; 

 trochanters, apices of femora, all tibiae, and all tarsi yellow, the apical joint of 

 hind tarsus blackish. In all other respects agreeing with the description of 

 mayetiolae. 



Male. — Unknown. 



Type locality. — Altamont, Calif. 



Type. — Catalog no. 44836, U.S. National Museum. 



