246 



THAXTER. — MONOGRAPH OF THE LABOULBENIACEiE. 



suffused with brown, the septa dark, the distal cell not conspicuously enlarged, becoming brownish; 

 the subterminal cell of the single terminal appendage examined, producing a blackish-brown, lateral, 

 irregular, spine-like outgrowth. Perithecium straight, more commonly solitary brownish yellow to dark 

 brown near the tip, not at all distinguished from the stalk, which is hyaline only at its narrow base, 

 the hyaline tip abruptly distinguished by a slight subtending ridge, its margins usually converging sym- 

 metrically to the truncate, or blunt apex. Spores about 45 X 3 fi. Perithccia, including stalk, 100- 

 120 X 20-24 fi. Appendages longer 60 X G /(. Total length to tip of perithecium 245-285 X about 

 22 ft. 



On Ardistomis viridis Say, Cocoanut Grove, Florida. November. On A. educta Bates, British 

 Museum (Biologia Collection), No. 676. 



The carabid hosts on which this form was found were collected under cocoanut palms along the 

 margin of Biscayne Bay. The species was seldom met with, and the male and female were associated 

 in every case; although, from the very minute size of the former, it is difficult to distinguish and suc- 

 cessfully remove it. The appendages are so closely approximated in pairs that they appear at first sight 

 to form a single row, only, on either side; and the presence of a second set below can only be determined 

 by very careful examination. Both this and the succeeding species represent a section of the genus 

 marked by a highly developed erect central axis, which results from intercalary growth, new cells being 

 added apparently as a result of the activities of the basal cell. 



Dimeromyces pinnatus Thaxter. Plate XXIX, Figs. 16-18. 

 Proc. Am. Acad. Arts and Sci., Vol. XXXV, p. 410. April, 1900. 



Male individual consisting of a basal cell more than twice as long as broad, the axis above of eight 

 or nine cells separated by horizontal septa/ all but the lowest and the terminal cell separating a small 

 cell on one side which forms the base of an antheridium or of a sterile appendage, the two organs diverg- 

 ing slightly from one another so as to form two vertical rows. Antheridium compound, short and stout, 

 the venter abruptly distinguished from the stout neck, the base of which is slightly enlarged and purplish 

 brown, the distal part tapering very slightly, the apex blunt. Appendages consisting typically of six 

 cells, including the basal cell, constricted at the dark septa, the distal cells suffused with brownish, the 

 terminal one larger, longer, and more or less vesicular, the thick walls tending to gelatinous degeneration. 

 Total length of receptacle 100 X 12 /i. Antheridia 35 X 12 fi. Appendages 50 X 7 fi. 



Female individual. Basal cell large and stout, the cells above it about twenty in number, greatly 

 flattened, the septa horizontal, a few of the lower cells having appendages on only one side, or none, the 

 rest bearing them on both sides. Appendages simple, consisting of from five to seven cells including the 

 basal cell, constricted at the dark septa, the terminal cell hyaline and much larger, as in the male; the 

 rest, except the basal one, purplish, or the upper one tinged with brown. Perithecia one to three in num- 

 ber, mostly rather slender, slightly curved outward; the stalk-portion about half as long as the remainder, 

 which is purplish brown, deeper distally; the tip well distinguished when not distended by spores, con- 

 sisting of a basal portion larger and slightly inflated, and a distal one formed by the lip-cells, abruptly 

 distinguished, its external margins generally symmetrically divergent, the four cells nearly equal and 

 symmetrical and ending distally in a corresponding number of papillae about the pore. Perithecia in- 

 cluding stalk, 125 X 20 fi. Receptacle 190-225 X 28 fi, not including basal cells of appendages. Ap- 

 pendages 55 X 8 //. 



On Ardistomis (?) sp., Hope Collection, No. 296. No locality, but probably Mexico or South 

 .America. At base of elytra and on leg. 



The determination of the host of this species is uncertain, but the insect is at least allied to A rdistomis, 

 The parasite is very peculiar and striking in appearance, and although closely allied to the preceding 

 species, differs markedly in the characters of the male, as well as in the arrangement and appearance of 

 the appendages and perithecia. Specimens occurring on the leg of the host (fig. 17), differ decidedly 



