EXPERIMENT STATION BULLETINS. 263 



fine threads (mycelium) bearing spores at their distal extremities. These 

 threads are usually simple, though sometimes bearing a few short 

 branches. They are septate at long intervals, granular, and contain vacu- 

 oles. The spores are lunate, bluntly rounded at both ends. In size they 

 measure about 50 microns long by 18 in diameter, some being as long as 

 55 microns and a few as short as 28 microns. They are finely granular, 

 with oil globules usually near the ends. In a single specimen large num- 

 bers of resting spores were found. In this case the mycelium had largely 

 disappeared. The resting spores were spherical, hyaline, with many small 

 translucent interior globules. They measured from 40 to 44 microns in 

 diameter. 



The fungus also was found at the same time on several specimens of 

 Muscidae, on a Cheironomid, and on Biplax, probably D. rubicundula. 

 Attempts were made to introduce the disease into new regions, but 

 with little success. In the laboratory, a large piece of bark bearing 

 mosq-uitoes killed by the disease was placed in a cage with many mos- 



Fiff. 9— Spores and resting-spores of mosquito disease i^Kiiloiiiophlhoru). greatly enlarged, Original. 



quito larvae and pupae. A few adults died after emerging but not 

 nearly all of them. 



On August 7, a number of pieces of bark covered with mosquitoes 

 killed by the fungus, were placed on the margins of a pool in the river 

 woods. The disease had not previously appeared in that section. On 

 August 13 a few dead mosquitoes were found near the place where the 

 infection was made. On August 23, the disease was widespread 

 throughout these woods, 



THE LONG LBCANIUM AND ifS FUNGUS DISEASE, 



Lecanium longulum. Doug.* 



A scale-insect, very common in our green-houses, is Lecanium longv,- 

 lum. It is found on Ficns very abundantly and also on Monsteria and 

 Groton. Fig, 10 shows this scale in its characteristic form, on a twig 

 of fig. Fig. 11 shows the same scale on a leaf of the same plant. The 



* Kindly determined for me by Mr. Theo. Persande of the Department of Agriculture, Wash. 



