178 ROLAND THAXTER ON THE 



Empusa (Entomophthora) virescens nov. sp. 

 PI. 18, figs. 251-201. 



Conidla ovoid to oblong, of irregular shape; with bluntly rounded base and apex, the 

 former often hardly papillate and not well distinguished from the apex : color greenish yel- 

 low in dried material; containing numerous small, irregular, often rod-like fat bodies; 

 measurements 10x20,,-16x36/j., average 14x30,./.. ConidiopJiores digitate, arising indi- 

 rectly from spherical hyphal bodies which germinate in all directions, giving rise to very 

 numerous hyphae which subsequently become conidiophores. Cy-stldia not observed. 

 Secondary conidia like the primary. Resting spores unknown. Host attached to sub- 

 stratum by rhizoids? 



Hosts. Lepidoptei-a : larvae o? Agrotls fennica. 



IlaUtat. Ottawa, Ontario (Mr. Fletcher). 



The specimens from which the above description was taken Avere received by Professor 

 Farlow from Mr. J. Fletcher, Dominion entomologist, who writes concerning them as 

 follows: — "In the spring of 1884 from May 15 until the end of the first week in June, 

 all the gardens and fields in the district around Ottawa were severely attacked by the 

 larvae of Ar/rotis fennica. The disease of which you have a specimen w^as first observed 

 about the 22nd of May, and was extremely virulent. Dead larvae were to be found in 

 all directions; on stone walls, on fences and particularly on the tops of stems of grasses. 

 They were also vigorously assailed by Tachinidae and Carabidae. The JEntomojMhoru, 

 however, was undoubtedly the influence which brought this insect down again to its 

 normal rai-e occurrence at Ottawa." The specimens received were black and shrivelled, 

 the fungus appearing as a greenish yellow coating, emerging in small tufts, which, in the 

 more mature si^ecimens, appear to have coalesced over the body. The conidia appear 

 also gi-eenish j'ellow in the mass, and are recognized by their general shapelessness and 

 rounded extremities, as well as by the mimerous small fatty bodies of a crystalline ap- 

 pearance which characterize the spore contents. I have placed this s[)ecies near E. Ajihi- 

 dis from the structural similarity indicated by the peculiar germination of the hyphal 

 bodies already described in the last-named form; but the conidia seem to be of a diflerent 

 type. 



It should be noted that the host of this species is closely allied to that of J^. mega- 

 sjjerma of Cohn which also occui's upon an A(jrotis larva. Mr. Fletcher Avrites me that 

 he has not observed a single specimen of the fungus since the date above mentioned, and 

 as the material originally sent contained only conidia I am unable to give any information 

 concerning the resting spores. The conidia of E. luegasperma are unknown, nor has the 

 species been observed to my knowledge since it was described b}' Cohn.^ The resting 

 spores of E. megasjjerina are fortunately an exception to the general rule, being readily 

 recognized by their dark brown, reticulate epispore, so that the question concerning the 

 identity of the present form with Cohn's species can be settled beyond a doubt as soon as 

 the resting spores of the one or the conidia of the other become laioAvn. 



' I. c. B. 



