FUNGUS OCCURRING IN PULVINARIA INNUMERABILIS. 313 



merited and appear very dark in fresh material ; a pair of these 

 are frequently rather closely fused to form an oval body. The 

 contents of these dark cells are highly granular, with the proto- 

 plasmic mass clearly separated from the cell wall by a hyaline 

 layer. Toward the tips the hyphse are usually much more slender, 

 pale in color and with only scattered granules in the protoplasm. 

 The method of branching is entirely dichotomous, many lateral 

 branches along the larger hyphse consisting of but a single cell 

 although both near the tips and on the larger hyphae there are 

 many long branches which again subdivide. Very rarely there is 

 an anastomosis of the finer apical branches formed by lateral 

 prolongations of the cells. In preparations we have had difficulty 

 in recognizing the conidiophores, but free conidia are present in 

 old cultures. They measure from 8-io/x in length and are 

 broadly oval in form, very nearly transparent and without color. 



SYSTEMATIC POSITION OF THE CULTIVATED FUNGUS. 



We have been unable to deal with this matter in a satisfactory 

 way owing to our un familiarity with cryptogamic botany and 

 must leave it for consideration by an experienced mycologist. It 

 is very evident that the symbiotic organism in Pulvinaria cannot 

 be regarded as a Saccharomycete, although its morphology and 

 method of multiplication in the insect does not preclude such an 

 assumption. Indeed, the symbionts that have been observed in 

 other Coccids and in most other Homoptera as well have usually 

 been regarded as yeast-like organisms and commonly referred 

 to the genus Saccharomyces or to new genera located in the same 

 group of plants. Berlese ('06) has placed the organism which 

 he cultivated from Ccroplastcs in the genus Oospora, thus recog- 

 nizing it as a true fungus, but hitherto, with the possible exception 

 of Pierantoni ('10) no one else seems to have been successful in 

 growing in vitro any of the symbionts of coccids. 



The species which we have obtained from Pnh'inaria seems to 

 be quite similar to the one described and figured by Berlese from 

 Ceroplastcs so far as the general morphology of the yeast-like 

 cells in the coccid and the mycelial structure in culture. Neither 

 species, however, has been sufficiently studied to make a more posi- 



