44:0 Agricultural Experiment Station, Ithaca, N. Y. 



dnced all ov^cr the surface of the potato, some of them measuring 

 2 to 3 cm. in length and 1 cm. in breadth. They are usually 

 flattened. 



SPOROTKICHUM MINIMUM Speg. 



On December 18, 1894, Mr. Martin, a student in the University, 

 found a large black ant, Camjyonotus, under the bark of a decaying 

 log. The insect was covered with a growth of white mycelium, 

 but no conidia were visible. It was placed in a moist-chamber for 

 a few days, when great numbers of small spherical conidia made 

 their appearance, borne in loose branching heads identical with 

 those produced in artificial cultures. Nearly the entire insect was 

 covered with a dense, white, felted growth of mycelium. 



On December 26th, a dilntiuii culture was made. After two 

 •days, the conidia become swollen and one or two germ-tubes are put 

 out which branch freely (Fig. 34). The threads are continuous and 

 tbe protoplasm is hyaline. Cylindrical spores, either short and 

 broad, or elongated, are thrown off in the agar (Figs. 35 and 36). 

 By the end of three days, the threads begin to emerge from the sur- 

 face of the agar. Many septa appear now irregularly placed. The 

 ■conidia appear on about the eighth day. The threads spread loosely 

 over the surface of the agar, and the short, lateral or terminal 

 branches bear flask-shaped sterigmata, either singly or in groups. 

 The microscopic growth on the plate is at first coarsely stellate, 

 afterward becoming finely radiate and more dense. A small, dense, 

 -conidia-bearing mass of mycelium is usually formed at the center 

 of the colony, and a looser tangle of threads bearing conidia usually 

 ■covers the colony, sometimes spreading over the entire plate. A 

 good deal of variation is noticeable. The periphery of the colony 

 is usually fringed with a fine feathery growth in the agar composed 

 of either curved or straight strands, made up of several filaments. 

 The sterigmata are flask-shaped and bear at the apex a single conid- 

 ium or more often three to six conidia collected into a compact ball, 

 probably held together by some viscid substance which prevents 

 their forming chains and draws back the ones first produced causing 

 them to adhere at the sides of the later conidia. 



On potato the growth spreads very slowly over the surface form- 

 ing a close felt, white, and not strongly raised from the surface of 

 the potato. The mycelium is yellow where it touches the glass. 

 No Isaria-sporophores are produced. 



