186 



ROLAND THAXTER ON THE 



only the minutest gnats and is thus very difficult to find. A small number of specimens 

 were taken at Cullowhee in July at different times; but I found it in no other locality 

 and it is apparently very rare. The conidia are very slender and readily separated from 

 those of E. conica by their fusiform shape, neck-like basal portion and constantly smaller 

 size, the maximum length being slightly over 4:5a. 



The species has no interest beyond the fact that it affords a second instance of the 

 peculiar "co/wca" type of conidia, and I can give no information concerning the resting 

 spores. 



Empusa (Entomophthora) conica Nowakowslu. 

 PI. 21, figs. 392-410. 



Entomophthora conica, Xowakowski I.e. A; I. c.B, p. 155, plates vnr and ix, figs. 1-32. 



Conidia long, slender, conical, often strongly curved with a rounded papillate base 

 tapering to the usually blunt extremity; 25-80 X 10-14/a. Conidiophores digitate, arising 

 as a rule directly from nearly spherical hyphal bodies and coalescing over the body of 

 the host in a clear white mass. Cystidia larger than conidiophores, rounded at apex. 

 Secondary conidia like the primary or broadly ovoid, rarely pointed at the apex. Rest- 

 ing spores, zygospores, produced by a SpirogyraAWe conjugation, usually budding from 

 one of the gametes; spherical, colorless, 30-50/* in diameter. Host attached to substra- 

 tum by numerous rhizoids. 



Hosts. Diptera: imagines of Chironomus and other small gnats. 



Habitat. Mt. Washington, 1ST. H., JSTorth Carolina, Europe. 



The singular shape of the conidia in this and the preceding species distinguishes them 

 at once from all other known Empusae although a transition from the ovoid type to this 

 elongate form is seen in E. sepulchralis, E. variabilis and E. rhizospora. The exact ad- 

 vantage of such a shape it is difficult to understand as the spores do not seem so well 

 calculated to hit and adhere to a passing host as the more blunt forms. In contrast to 

 this elongate form the secondary conidia of the second type are extremely compact, 

 sometimes approaching those of E. Muscae in shape. The separation of the conidium 

 proper from the mother cell wall is very commonly seen in this as in other species which 

 vegetate in very moist situations, and the tendency of the spore contents to become more 

 or less contracted is often observable; the contracted portion separating itself from 

 the empty extremity by a cross partition (fig. 396). The conidia themselves vary consid- 

 erably in size and shape, in the bluntness of their apices which I have never seen as sharply 

 pointed as is represented in JS"o wakowski's plate, and in the relative thickness of the spore 

 and its amount of curvature. With regard to the curvature of this and other elongate 

 forms, a natural explanation seems to be afforded by the deviation of the conidiophores 

 from a perpendicular position which is usually more or less considerable except in the 

 upper middle portion of the mass. The conidia, while in process of formation, endeavor 

 to correct this deviation by curving upwards thus giving rise to the strongly curved 

 elongate forms as well as to the abruptly bent bases so commonly seen in the ovispora 

 type. It is noticeable that this curvature is rarely, if ever seen in Empusae of the sphae- 

 rosperma type; and the reason for this is very evident in view of the peculiar mode of 



