ENTOMOPHTHOREAE OF THE UNITED STATES. 179 



Empusa (Entomophthora) Americana nov. sp. 

 PI. 18, figs. 262-273. 



Conidia long-ovoid, with a broad evenly rounded apex; tapering for some distance to 

 a papillate l)ase often slightly bent to one side. Within the spore are usually niunerous 

 fatty bodies often very rcgiilar in size and shape. Average measurements 28-30/1 x 14//, 

 maximum 35 x 15/'. ConidiojjJiores regularly digitate, arising from large, irregulai-, round- 

 ish hyphal bodies, and coalescing over the host iu a mat-like covering which becomes 

 slightly rust colored on exposure. Gystidia absent. Secondary conidia like the primary. 

 Resting spores, colorless, hyaline, sphei-ical; average diameter 38-45/., maximum 50//, 

 Process of formatiou not satisfactorily observed. Host attached to sul)stratum by num- 

 erous filamentous I'hizoids, without terminal root-like expansions; forming an even mat- 

 like attachment continuous around the abdomen of the host. 



Hosts. Diptera : Musca domestica, M. vomitoria, Lucilia Caesar, and numerous other 

 large flies. 



Hahitat. Xew Eno-land and Xorth Carolina. 



This common species is freqiiently met with from June to October on the borders of 

 woods, near brooks or in shrubbery about houses. The host is generall}' found fixed to 

 the under, i-ai-ely on the upper, side of leaves or on bare twigs, a few feet fi'om the 

 ground. It can readily be distinguished by its general habit from any species known to 

 me with the exception of JE. ecJiinosjJora / since the rhizoids instead of growing out in the 

 form of numerous scattered threads are developed in an even layer around the hosts' 

 body forming, with the conidiophores, a continuous mat-like covering Avhich becomes 

 often dark rust colored on exposure to the weather. The mass of conidiophores is at 

 first pure white, and in a moist chamber grows with great luxuriance. 



The conidia are almost identical in appearance with those figured by N^OAvakowski as 

 belonging to E. oinspora and the measurements are very nearly the same. U. ovispora 

 is, however, at once separated from the present species by its peculiar cystidia whicli re- 

 semble those belonging to E. sepulchralis (fig. 306). In the present species, I believe 

 there are no cystidia whatever, and I have looked in vain for anything* remotely resem- 

 bling them. Whether the type of conjugation found by iN^owakowski in J^. ovispora 

 exists also in the present species, I am unable to say, since in all cases in Avhich I have 

 found resting spores, the latter were mature and no trace of their method of produc- 

 tion was visible. £/. Americana is also closely allied to JiJ. muscivora of Schroeter which 

 seems to be identical with JS. CalUphorae of Giard. The resting spores in both these in- 

 stances are described as chestnut or deep chestnut l)ro\vn; and since the material of both 

 seems to have been abundant, I have no hesitation in separating them from our species 

 in which the spores are always perfectly hyaline. They occur not infrequently in con- 

 nection with the conidia, and my material is sufficiently large to demonstrate the invaria- 

 bility of their color or lack of color. In l^orth Carolina the species Avas of i-arer occur- 

 rence than in Xew England, and I obtained l)ut few specimens on shrubs in open woods 

 or on twigs of hemlock. It has been taken also by Professor FarloAv and Mr. Miyabe at 

 Woods HoU, Mass., and a specimen Irom jN^ew Hampshire Avhich I have not examined 



