260 



THAXTER. MONOGRAPH OF THE LABOULBENIACE^E. 



Dichomyces in^equalis Thaxter. 

 Syn. PeyritschieUa nigrescens Thaxter. 



I have already called attention to the fact that Peyritschiella nigrescens figured in my monograph is 

 undoubtedly a "reversion" of this species to the PeyritschieUa-condition, a phenomenon which is likely 

 to occur in all the species of Dichomyces when the individuals grow under unfavorable conditions, as on 

 the legs of the host. The typical D. inccqualis seems to occur only on Phihmthus debilis and is very con- 

 stant in its characters. A single specimen of this host in Dr. Sharps collection, No. 1213, from Scotland, 

 was found infested, and the individuals correspond exactly to the American types. 



PEYRITSCHIELLA Thaxter. 

 I have already called attention to the close connection of this genus with Dichomyces from w hich 

 it differs only in its asymmetrical habit, and also to the fact that a majority of the species of the latter 

 genus assume the typical Peyritschiel/a-ty\)v when growing under unfavorable conditions as on the legs 

 of their hosts. Despite this fact I feel that the two genera are best kept apart, and are sufficiently dis- 

 tinguished. 



Peyritschiella protea Thaxter. Plate XXX, figs. 8-9. 

 Proc. Am. Acad. Arts and Sci., Vol. XXXV, p. 427. April, 1900. 



Perithecia translucent, brownish amber-colored, rather stout and symmetrically inflated, the sym- 

 metrical tip tapering rather abruptly, the apex rather narrow truncate, the lip-edges unmodified. Recep- 

 tacle nearly or quite hyaline, consisting of a single basal cell, above which the three typical tiers of cells 

 are very variously developed: the lowest of these may rarely consist of a single cell, often of three which 

 do not project laterally, or in well-developed specimens of as many as twelve or more cells, those external 

 to the middle three forming on either side distal external angular usually asymmetrical projections, one 

 or both of which may bear terminally one or even two perithecia and typical appendages: the middle 

 series like the lower, when the latter is well developed, subtriangular in form, consisting of sometimes 

 as many as fifteen to eighteen cells, generally somewhat asymmetrical; a single perithecium usually aris- 

 ing distally from the projecting portion on either side, together with numerous typical appendages: the 

 distal tier similar to the middle one, mostly smaller, somewhat asymmetrical, bearing usually a single 

 perithecium above the median cell, though not produced from it, the remaining cells bearing typical 

 appendages, often as long or longer than the perithecium, the small subtending cell being unusually 

 well defined. Subject to great variation, and sometimes producing more than one antheridium. Peri- 

 thecia 80-96 X 32 ji. Receptacle 270 X 80-100 to 120 X 45 fi. Total length to tip of perithecium 

 200-350 t i. 



On Blcdius bicornis Germ., British Museum, No. 392, Europe (Thuringia), No. 432, Europe; on 

 Oxytelus rugosus Fabr., British Museum, No. 450, Hampstead, England; on Acrognathus mandibularis 

 Gyll., British Museum, No. 434, Europe; on Oxytelus sp., Fresh Pond, Cambridge. On legs, elytra, 

 and prothorax. 



In small specimens the two lower tiers may be but slightly developed, bearing neither appendages 

 nor perithecia, the middle producing one antheridium, the number of cells and appendages on one side 

 of the perithecium being, as in all species, greater than on the other. Occasionally, as in fig. 9, accessory 

 perithecia may develop from the middle or even the second tier, and a second antheridium, even, may 

 arise; but such conditions are abnormal. Although the simplest individuals differ so widely in appear- 

 ance from those more highly developed, I think that I am right in placing under this species all the forms 

 here included. The specimens from Bledius bicornis are regarded as the type forms, and both figures 

 have been drawn from this material. 



