442 Agricultural Experiment Station, Ithaca, N. Y. 



IS ARIA VEXANS N. SP. 



A larva of Lachnosterna found April 7, 1894, bj Mr. M. Y, 

 Slingerland in a breeding-cage at the insectary, was completely 

 covered with a felted white coat of Sporotriclmm globuliferumy 

 bearing patches of creamy-white conidia. A microscopic examina- 

 tion showed the fructification to be exactly as in the case of the 

 typical SpoTotrichum glohidiferwm. A dilution culture was made,, 

 and germination became apparent at the end of one day. The 

 development is as follows : The nearly spherical conidia become 

 swollen and produce a germ-tube which grows in a sinuous line^ 

 branching occasionally and producing many long, cylindrical conidia 

 in the agar. These are borne at the end of a filament, and each 

 spore is successively pushed aside by the one next produced, result- 

 ing usually in a cluster of spores placed side by side (Fig. 18). 

 Branching soon commences and septa are often present just beyond 

 the base of the branches. Small vacuoles appear, usually irregularly 

 placed. At the end of about three days the growth api)ears above 

 the agar in loose, cottony filaments, each colony becoming circular 

 in form and finely radiated. After one more day the conidia appear 

 (Fig. 16). Short sterigmata bear one or two conidia on short pedi- 

 cels. These conidia increase in number and the sterigmata lengthen 

 and multiply until at the end of a week large heads are formed 

 (Fig. 20). The threads anastomose freely (Fig. 15). In places, 

 where the colonies have been crowded they assume a smaller stellate 

 form instead of the ordinary circular form. 



On potato the growth spreads over the entire surface in a felted 

 layer, afterwards becoming densely covered with a farinaceous, 

 creamy-wbite layer composed of colorless conidia. Isaria-sporo- 

 phores are often produced. In 1 tube are 10, ranging from 2 to 4 

 mm. in height. They are usually clavate in form, being sometimes 

 3 mm. in diameter at the apex, tapering to 1 mm. at the base. On 

 one side a long, pointed sporophore springs from a point near the 

 glass, but free from it. It is slender and measures 8 mm, in length 

 by about 1^ mm. in diameter at the base. At another point 2 

 about 1 mm. broad spring from the same base, where the potato 

 touches the glass, and grow to a length of 1 cm. They are flattened 

 and cling to the glass of the tube for their entire length. Wherever 

 the mycelium touches the glass it is seen to have a bright bufl: color. 



