Jan. IS, 1920 Further Studies of Sorosporella uvella 411 



first few days of the incubation period. Three or four days prior to 

 death, however, they become sluggish and eat sparingly; and one or two 

 days before death a change in outward appearance may be observed. 

 The chitinous body wall of healthy larvae of Feltia annexa, one of the 

 hosts employed, is dorsally opaque and flecked with irregular dull brown 

 patches. Ventrally it is somewhat translucent, in fact so much so that 

 some of its internal organs are visible. When afflicted with this disease 

 the larvae typically turn a creamy white color a day or two before death. 

 If the flaccid body is pricked with a needle, a greenish or whitish liquid 

 appears in which, if it is examined microscopically, yeastlike cells can be 

 readily detected. These cells may be formed in enormous numbers and 

 when abundant in the insect cause the blood to appear white, while if 

 there are few yeast cells present the normal green color of the blood 

 prevails. 



Occasionally red-colored patches appear a few hours before death, 

 either posteriorly, anteriorly, or, more commonly, near the middle of the 

 body. They are more noticeable on the ventral surface because of the 

 lack of pigment in this region. Dissections show that mature resting 

 spores are present in such areas ; and their early occurrence and maturity 

 in such spots possibly indicate the seat of infection, although, as noted 

 below, the detached yeastlike cells which later develop into resting spores 

 are distributed throughout the body cavity by the blood of the insect in 

 such a way that a local early maturity of the chlamydospores would 

 seem impossible. 



In one or two instances the whole middle portion of the body of an 

 infected insect became reddish and noticeably shrunken, the anterior 

 and posterior ends retaining the normal greenish, turgid appearance. 

 The prolegs of such diseased portions showed no reaction when pinched 

 with a pair of forceps, but the true legs at the anterior part of the body 

 reacted when similarly treated. 



With the exception of such symptoms, which, as has been stated, occur 

 only in the later stages of the disease, there are no others prior to death, 

 so far as the writer is aware, which indicate the presence of Sorosporella. 



Death follows a day or two after the natural pigment of the insect dis- 

 appears; and the creamy white color soon changes to pink, the latter 

 usually appearing simultaneously over the whole body and becoming 

 more and more intense until the final development of the organism, indi- 

 cated by the brick-red color, is reached. The disease can thus be readily 

 recognized at any time after death without the aid of a microscope. 



In contrast to most known species of entomogenous fungi (except cer- 

 tain species of Entomophthora which form resting spores only), Soros- 

 porella completes its entire development within the body of its host, 

 producing no growth externally. 



Shortly after death the body appears shrunken and wrinkled. It is 

 somewhat flattened, and there is nearly always a longitudinal, ventral, 



