KNTOMOPIITIIOREAE OF THE UNITED STATES. 



179 



Empusa (Entomophthora) Americana nov. sp. 

 PI. 18, BgS. 262-273. 



Conidia long-oyoid, with a l)r<>;i<l evenly rounded apex; tapering for some distance to 

 a papillate base often slightly bent to one wide. Within the spore are usually numerous 

 fatty bodies often very regular in size and shape. Average measurements 28-30// X 1 b,, 

 maximum 35 x 15p. Conidiophores regularly digitate, arising- from large, irregular, round- 

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

 slightly rust colored on exposure. Cyst id i a absent. Secondary conidia like the primary. 

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

 Process of formation not satisfactorily observed. Host attached to substratum by num- 

 erous filamentous rhizoids, 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. 



Habitat. New England and North Carolina. 



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

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

 the under, rarely on the upper, side of leaves or on bare twigs, a few feet from the 

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

 me with the exception of E. ecliinospora ; 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 which 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 Nowakowski as 

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

 is, however, at once separated from the present species by its peculiar cystidia which 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 Nowakowski in E. ovispora 

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

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

 tion was visible. E. Americana is also closely allied to E. muscivora of Schroeter which 

 seems to be identical with E. Callipliorae of Giard. The resting spores in both these in- 

 stances are described as chestnut or deep chestnut brown; 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 North Carolina the species was of rarer occur- 

 rence than in New England, and I obtained but few specimens on shrubs in open woods 

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

 Woods Holl, Mass., and a specimen from New T Hampshire which I have not examined 



