Entomogenous Fungi. 429 



closed by an inverted jar intermediate in size between the two. 

 The moss packing was moistened daily, thus maintaining a humid 

 atmosphere suitable for the best growth of the fungus, and approxi- 

 mating the conditions of the natural fall and spring home of the 

 caterpillar. 



ISARIA TENITIPES Peck. 



The material from which the present study was made was ob- 

 tained during the summer of 1894. Prof. Atkinson collected two 

 specimens on the pupse of unknown Arctiids, buried in leaves. 

 From seven to ten slender, clavate sporophores arise from 1 to 1^ 

 cm. above the pupae. The distal half is flattened and densely cov- 

 ered with a farinaceous white powder composed of colorless conidia. 

 Tiie base is greenish-yellow and sterile. The conidia are oval to 

 globose, hyaline, and measure from 2^ to 3^ microns in size. 



On plate cultures germination becomes apparent in about twenty- 

 four hours. The conida become swollen and put out from one to 

 three slender germ-tubes which grow in a sinuous line from one or 

 both ends of the conidium. A slight constriction and sometimes a 

 septum separates the conidinm from the base of the germ-tube. 

 Often one or two vacuoles are present near the base of the largest 

 germ-tube. The protoplasm is usually hyaline and homogeneous. 

 After about forty-eight hours the threads appear above the agar in 

 circular tufts. Many small and irregular vacuoles appear in the 

 threads. Septa are sparingly and irregularly placed throughout the 

 entire colony, and the branches are slightly constricted at the base. 

 At the end of three days, the vacuoles become more thickly and 

 regul irly placed. The colonies by this time all appear above the 

 surface of the agar, and some conidia are produced. The threads 

 standing above the agar, bear short branches either in whorls, or 

 placed in an opposite manner after the type of Verttcillinm. The 

 conidia are borne either on the ends of these short branches or on 

 short flask-shaped sterigmata grouped at the apex of a short branch. 

 Those first produced cling to those next succeeding and so on until 

 from two to eight conidia are collected forming a small spherical 

 mass or sometimes an irregular chain. At the end of about four 

 days, the threads usually spread over the surface of the plate in an 

 even, flocculent layer, the colonies showing as points of denser 

 growth. In case the conidia are thinly sown in making the dilution 

 culture, the threads confine themselves to the colonies and do not 

 spread. 



