MONOGRAPn OF TIIE LABOULBENIACEiE. 



351 



Laboulbenia variabilis Thaxtcr. Plate XXI, figs. 1-4. 



Proc. Am. Acad. Arts and Sci. Vol. XXVII, p. 38. 



Nearly hyaline or suffused, sometimes deeply, with smoky brown. Perithecium straight and 

 rather narrow, or stout and inflated ; hyaline or deep smoky-brown, blackened deeply below the 

 hyaline tips of the lip-cells, which are rather coarse and turned slightly outward or nearly 

 straight. Appendages numerous, arising from as many small cells, which take the place of the 

 ordinary insertion-cell, several times sub-dichotomously branched, the lower three or four septa 

 blackened and oblique, the cells between them inflated, the ultimate branchlets straight, tapering, 

 rather slender, erect or slightly divergent. Antheridia borne on short branchlets about the 

 lower portion of the appendages, forming a conical cluster and arising laterally as well as ter- 

 minally in variable numbers. Receptacle normal, except that cells IV and V may be distally 

 and irregularly divided into a few small cells ; short and stout or very elongate, hyaline or 

 wholly or partly suffused with smoky brown, the darker portions punctate. Perithecia, 100 X 

 225-35 x 125 Appendages, longest, 475-500 /j,. Total length to tip of perithecium, 180 p to 

 1.65 mm. Spores, 50-75 x 6-7 fi. 



On Anomoglossus pusillus Say, Chlcenius cestivus Say, C. cumatilis Lee, O. cursor Chev., C. 

 leucoscelis Chaud., C. floridanus Horn, O. pennsylvanicus Say, C. rvficauda Cliaud., O. sparsus 

 Lee, C. texanus Horn, C. tricolor Dej., C. viridicollis Reiche, Omophron americanum Dej., Omo- 

 phron spp. indet., Nebria pallipes Say, Pterostichus adoxus Say, P. luctuosus Dej., P. corvinus 

 Dej., P. caudicalis Say, P. Sayi Brulle, Patrobus longicornis Say, Platynus extensicollis Say, 

 Maine to Florida and Texas, Utah, Nebraska, Washington, California, and Mexico. On Pterosti- 

 chus (?) sp., Brazil. 



This species is remarkable for its great variation in size, even on the same host ; specimens 

 on Pterostichus caudicalis measuring over a millimeter and a half, while many individuals on 

 Omophron are less than 200 fi in length. The form and relative position of the perithecium 

 also differs very considerably, and in one instance the tip of the perithecium scarcely exceeds 

 cell V, being united to the receptacle throughout its length. Although their number and length 

 varies very greatly, the species is always readily recognized by the character of the appendages 

 and their insertion on an irregularly cellular base, which is made up partly from divisions of an 

 original single insertion-cell and irregular terminal divisions of cells IV and V. It is a common 

 form, occurring on all parts of its hosts, though preferring definite positions in certain cases, as 

 for example in Pterostichus luctuosus, where it is usually found along the edges of the elytra, 

 especially the left near the base. It grows usually scattered, but often rather closely crowded. 

 It is more closely connected with the aquatic forms than any other species, unless perhaps L. 

 armillaris, through the irregularity of the cells which form the base of insertion of its append- 

 ages, and affords a connecting link which renders the exclusion from the genus of the first 

 mentioned forms quite unwarrantable unless they may prove to present essential variations in 

 their sexual processes. 



The material from South America, which was obtained from specimens of a Brazilian Ptero- 

 tichus (?) in the Museum of Comparative Zoology, was found on the legs and on the lower sur- 

 face of the thorax of the host, and although some of the specimens are peculiar in habit, 



