emery: SIMULIUM VITTATUM in KANSAS. 331 



Some of the eggs were laid on old leaves in the ripple. N. Y. 

 St. Mus. Bui. 47, p. 408, gives the following on oviposition : 

 "The place selected is always at the edge of a little waterfall, 

 on a surface that is intermittently washed by the swaying cur- 

 rent, and so kept wet. Here the females flock and pile up 

 great white masses of eggs, which with a little age turn yel- 

 lowish. Waves dash over them while ovipositing, and often 

 sweep them away, but they at once return to their task." 



The description of an egg mass is given in my field notes 

 for October, 1911, as follows: "SimiiUum eggs when first de- 

 posited are whitish or creamy in color. In two or three days 

 they begin to turn yellowish, becoming later a rusty yellow, 

 then brownish to a dark brown, almost black at time for 

 hatching. All this time they retain a shiny appearance. The 

 empty shells after the larvse have hatched look dull, tattered, 

 torn, and sunken in, soon breaking to pieces in the rippling 

 water. When first hatched a larva is so small and light in 

 color that one can hardly see it on a rock with the unaided 

 eye. On account of the reflections of a wet rock it is even 

 difficult to see with a 12 )< lens if the larva is not moving." 



A variation in the length of the incubation period is shown 

 in my field notes. "October 26, 1911. — Discovered very small 

 larv^, 1 mm. long, on rock with egg mass that I found October 

 19. Yesterday the eggs were full; to-day many of them 

 were sunken in. October 28. — Found more small larva; on 

 rock with eggs discovered October 19. October 30. — Part of 

 the eggs laid on the rock that I placed in the ripple for that 

 purpose October 23 are rusty yellow and very shiny. No- 

 vember 2. — Creek partly frozen over. Eggs of October 23 ap- 

 parently still unhatched, but covered with a dirty slime like 

 empty shells. Part of them were hatched, though I could find 

 no young larvse with them. 



The dates from October 19 to 26 show a period of eight days, 

 while that from October 23 to November 2 shows a period of 

 eleven days for incubation. That variation is due, no doubt, to 

 the decrease in seasonal temperature to freezing. 



Now the length of the larval stage may also vary. Taking 

 the periods between the broods previously mentioned — that is, 

 from the fore part of April to the middle of July, and from 

 mid-July to the latter part of October — we find the length of 

 life cycle during the warmer months to be approximately 

 three months and one week. Allowing five to six days for the 



