LAWSON: KANSAS CICADELLID^. 23 



ing eggs being deposited in the rose, while the eggs for the 

 second generation are deposited in apple. Here we seem to 

 have a good case of alternation o f gon^ration c , for only a very 

 small percentage of these insects remain on the apple, their 

 summer host, to deposit overwintering eggs. Of course where 

 a species is a general feeder, it may oviposit in any of its host 

 plants. 



The eggs are usually whitish, elongate, and often slightly 

 curved. Before they hatch the eyes of the nymphs are usually 

 seen as distinct reddish spots. 



Comparatively little is known concerning the number of 

 eggs deposited by a single individual. In some cases the num- 

 ber seems to be quite low, while in others it is rather large. 

 Some grass-feeding species deposit a few eggs together ; others 

 as many as fifty side by side. Osborn states that Parabolocra- 

 tus viridis may lay as many as 120 eggs in a single hour. Of 

 course eggs deposited under the sheaths of the grass blades are 

 more readily found than those deposited in the leaf or stem. In 

 the case of the latter, however, a blister-like swelling seems to 

 develop around the eggs shortly after deposition, which helps 

 in locating them, or the leaf may be held up to the sunlight and 

 the eggs often discovered. 



The period of incubation varies greatly in length. Eggs laid 

 in the fall hatch the following spring or summer, the egz stage 

 thus lasting several months. Eggs laid in the spring or sum- 

 mer hatch in varying lengths of time. Osborn gives an aver- 

 age of about a month for the duration of the egg stage of 

 Dorycephalus platyrhynchus, and 10 to 17 days for Deltoceph- 

 alvs inimicus. Gibson gives 5 to 17 days as the length of the 

 incubation period for eggs of Ace rata gallia sangidnolenta dur- 

 ing the summer in the latitude of southern Illinois, and from 3 

 to 35 days, with an average of 12 days, depending upon the tem- 

 perature, for eggs of Drxculacephala mollipes in southern Ari- 

 zona. 



The nymphs are readily recognized as the young of Cica- 

 dellids, usually having more or less of the form of the adult 

 except for the wings, though usually lacking most of the colora- 

 tion of the adult till just before or after the last molt. During 

 the nymphal stage the wings are represented by wing pads 

 which gradually increase in size, but even just before the fifth 

 or last molt they are much smaller than the wings of the adult. 



