278 NARIATIOX.S OP THE SPOROCYST IS SAPROLEGNIA, 



3. Achilla eoiulitiun. wliert- the tirst iiKitile phase is merely represented by 

 the liberation of the spores, which encyst in a mass near the mouth of the sporo- 

 cyst. The second motile jjhase occurs later. 



■i. Dictiiuchus condition, where the spores encyst within the sporocyst, re- 

 gardless of the terminal opening formed for their exit. Later, the spores leave 

 their cyst cases, enter upon the second motile phase, pass out through the 

 terminal opening, often pushing their empty cyst cases befoi-e them. A second 

 Dictyuchus condition is described* where the zoospores pass directly through the 

 wall of the sporocyst. There is no definite statement as to how the zoospores 

 pass through the sporocyst wall, but from Lechmere's figure 17 we can only 

 infer tJiat the sporocyst wall degenerates at certain places to allow the escape of 

 the zoospores. 



5. Aplanes condition, where all motility is suppressed, and germination is 

 direct within the sporocyst, the germ tubes growing out through the wall of the 

 sporocyst. 



A variation of the sporocyst known as the "Dictyuchics-torm." was recorded 

 for the Saprolegniaceae prior to Lechmere's work. Hartogt refers to this form 

 in his analysis of the genera in the Saprolegniaceae , as follows : — 



"Dictyuchus-iorui. When the spores of Achlya or Saproleynia fail to leave 

 it [the sporocyst] at maturity, they encyst within, constituting this fomi or 

 dictyosporange. They either swarm ultimately in the second form or germinate 

 in situ by emission of a hypha." The "Dictyiichiui-lLorm" of Hartog is evidently 

 the dictyosporocyst of Lechmere wliich includes the Dictyuchus and Aplanes condi- 

 tions. 



In the present investigation, which was made upon material growing under 

 natural conditions as well as upon white of egg cultures, the writer observed 

 sporocysts of the Lepiolegnia, Pythiopsis, Achlya and Aplanes types similar to 

 those described by Lechmere. In addition, certain remarkable composite sporo- 

 cysts were observed which combine the characters of from two to four genera; 

 also a new Dicti/uchtis condition which diffei's from either of those described by 

 Lechmere.t 



Material was selected from the body, legs, wings and antennae of the in- 

 sect in order to ascertain whether the sporocyst variations were restricted to any 

 particular part of the host, and whether their occurrence is influenced by the 

 amount of available nutriment. Although the general growth of the hyphae was 

 found to be more vigorous upon the body of the insect, the abnornial sporocysts 

 occurred freely on all parts. 



Upon transferring part of the material to tap water in the laboratory, the 

 production of sporocysts was stimulated in both old and young hyphae. Young 

 liyiihae show a preponderance of the normal Saprolegnia type of sporocyst in 

 which two motile (iliases were observed. In old hypliae, however, the new sporo- 

 cysts often form within or at the base of three or four discharged sjjorocysts. In 

 these cases some of the new zoospores find dilliculty of escape, and encyst during 

 their passage through the old dischai-ged sporocysts (Text-fig. 1). Encystment 

 within the sporocyst under these conditions is found to occur at apin-oximately 

 the same time as that of zoospores which succeed in escaping. Retained zoospore."; 



•Now Phytologist, x., 191.1, pp. 167-203. 



+Ann. Bet., xi.. 1888-89, p.20;{. 



♦New Phytologist, ix., 1910, 1...W8: aii.t x.. liltl, p.lO; 



