EXPERIMENT STATION BULLETINS. 



267 



position. Fig. 17 shows a similar larva with the tube evaginated. In 

 this case, the ring with the six hairs is clearly seen. The young larvae 

 are covered with a very thin coat of wax and are marked with a num- 

 ber of transverse lines or fasciae, which become obscure with age. 



This pest is attacked and killed annually by a fungus (Isaria lecanifera 

 sp. nov.) noticed on this page. But for this fungus disease the scale 

 would be of considerable importance in green-houses. 



i^^i'iili 



; mm ' 



Fig. 17.— Same as Fig. 16. anal tube evaginated. 

 THE FUNGUS DISEASE OF LONG LECANIUM. 



Isaria lecanifera sp. nov. 



For the past five years, at least, there has been present in the Col- 

 lege green-house a fungus disease working on scale-insects of the spe- 

 cies known as Lecanium longulum. Its work has been so effective that 

 it is at times very difficult to obtain specimens of the insect host. The 

 whitened bodies of the dead coccids are everywhere, but with very few, 

 if any, health}' scales to be seen. 



On February 8, 1902, several good specimens of the diseased scale 

 were obtained from the green-house and dilution cultures were made. 

 When working normally on the scale, the fungus forms a dense felt, 

 sometimes merely bordering the scale with radiating filaments, some- 

 times making a thin film over the back of the coccid and at other times 

 becoming thickened and covering the scale entirely and hiding it from 

 view. The color of the growth is white or yellowish-white, sometimes 

 distinctly egg-yellow. 



No Isaria sporophores were seen, but the fungus is placed in the 

 genus Isaria because of its very close affinity to the Isaria stage of 

 Gordyceps clavulata. The gonidia are oval, from 21/2 to 4 microns long 

 and about 2l^ microns in diameter. 



'JpCHNICAL DESCRIPTION OF FUNGUS DISEASE. 



On Agar Agar — After six days, the growth in agar agar plates h^d 

 progressed so well that bits of growth were taken out and placed in 

 tubes of sterilized wort. No gonidia were produced on agar. In wort 

 the growth was rapid and luxuriant. One of the pieces of agar floated 

 on the wort and in three days the growth had become one-fourth of an 

 inch in diameter, being nearly hemispherical in form. A bit of 

 growth that sank grew on the bottom, trying to put up a forest of fine 

 filaments to the surface of the wort. In five days, the mycelium under the 



