THAXTKR. — MONOGRAPH OF Til 10 LA HOULBENIACFJTC. 



245 



hers on the abdomen of the host, and eventually are very evidently injurious in their effects, causing the 

 abdomen to become brown and more or less shriveled. I know of no other instance in which an evident 

 injury results from the parasitism of any member of the group. In both species the sexes are apt to 

 become separated or irregularly disposed, although their occurrence in pairs is a normal condition. 



Dimeromyces CRisPATU.s Thaxter. Plate XXIX, Figs. 14-15. 

 Proc. Am. Acad. Arts and 3d., Vol. XXXVI, p. 413. March, 1901. 



Male Individual. Receptacle consisting of four superposed hyaline cells, the basal one much longer 

 than the rest combined; the upper bearing distally a two-celled terminal appendage, the lower cell of 

 which is small, the upper elongate, brownish; the two remaining cells of the receptacle producing each 

 a single antheridium. Antlieridia superposed, the stalk-cell, neck, and venter well distinguished, the 

 latter symmetrically and considerably inflated, the neck slightly curved. Receptacle 50 X 8 /<. An- 

 tlieridia 33 X 8-9 /x. Appendage 36 fi. 



Female Individual. Receptacle consisting of usually five superposed cells, the basal cell very elon- 

 gate, slender, and hyaline; while of the four remaining cells the two lower are much flattened, broader 

 than long, and separated by oblique septa, the two upper unlike and narrower. Of these four cells the 

 second from below gives rise to the stalk-cell of the perithecium, while the others by successive prolifera- 

 tion produce each a branch consisting of eight or ten obliquely superposed cells; while each of these 

 cells in turn produces a single simple branchlet from its upper side, originally terminal, but becoming 

 lateral through the further proliferation of the cell which bears it; the branchlets distinguished by a 

 slight constriction and a broad dark septum at the base, brown, curved, distally helicoid, slightly enlarged 

 and paler. The primary terminal appendage thus appears as the lowest of the upper series of branchlets, 

 from which it does not differ in structure. Perithecia one to three in number, the first lowest, and always 

 formed from the second from below of the four distal cells of the receptacle, others sometimes arising 

 from each of the two upper distal cells; the stalk hyaline, long and slender, the venter small, narrow, 

 not distinguished from the stalk, becoming brownish, distally slightly inflated, the neck short and well 

 but not abruptly distinguished; the tip well differentiated, hyaline, symmetrical or nearly so, shovel- 

 shaped or spathulate, swollen at its base, and tapering to the broad, bluntly rounded or nearly truncate 

 apex. Spores about 30 X 3.5 fi. Perithecium: 70-75 X 18 ji, the stalk 50-125 X 15 fi. Receptacle 

 basal cell 185-250 X 18 ji, the distal portion about 50 /(. Total length to tip of perithecium 360-435 /x. 

 Lateral cell-series or branches about 50 (i long, their branchlets to tip of helix about 50 fi. 



On the legs and superior surface of the abdomen of the same host parasitized by D. coarctatus. 

 Ralum, New Pomerania. Berlin Museum, No. 1282. 



This species occurred very rarely and always in solitary pairs on various parts of the host, no in- 

 stance being observed in which a male failed to develop at the base of the female. It is more highly 

 differentiated than any of the other species in that the upper cells of the receptacle proliferate to form 

 several appendiculate branches. The species is further well distinguished by its curled appendages, 

 elongate basal cell, and peculiar long-stalked perithecia. 



Dimeromyces NANOMASCULUS Thaxter. Plate XXIX, Figs. 10-13. 

 Proc. Am. Acad. Arts and Sci. , Vol. XXXV, p. 411. April, 1900. 

 Male individual very minute, consisting of three superposed cells, the upper bearing a terminal 

 two-celled appendage with dark septa, the subbasal cell giving rise to a single small antheridium, the 

 neck usually abruptly turned to one side. Total length to tip of appendage 35 ft; the antheridium about 

 15 X 5 ft. 



Female individual consisting of a main axis of superposed cells from which appendiculate cells are 

 separated on both sides, the basal cell large and long, narrower below; the cells above about ten to fif- 

 teen in number, usually roundish; the appendages borne side by side in pairs on both sides of the recep- 

 tacle, mostly five-celled above their basal cells, sometimes curved or almost hooked distally, variably 



