36G W. D. FUNKHOUSER 



mate dates of emergence of the nymphs have been noted in the preceding 

 section of this study with reference to each species, but it may be interesting 

 to note more definitely the field records for certain species. 



The first nymphs to appear are those of Ceresa horealis, which have 

 been taken on April 15. Nymphs of Ceresa taurina are recorded for April 

 26. Eticfienopa binotata has been recorded on May 3, Ceresa huhalus .on 

 May 10, Ceresa diceros on May 20, Vanduzea arquata on May 29, and Thelia 

 bimaculata on May 30. During the first week in June most of the other 

 species appear in rapid succession, and by the first of July all are out 

 that are to be expected. 



Meanwhile the two species that are known to winter over in the adult 

 stage — E^itylia hactriana and PubliUa concava — appear sporadically in 

 the warmer days and vary the dates of their appearance from season to 

 season according to the weather. The appearance in the field of the adults 

 of most of the species depends of course on the time required for the 

 matiu'ing of the nymphs, which varies with the species. Collecting 

 begins on July 1 and lasts until the end of September. 



MATING 



Mating begins almost immediately after the insect reaches maturity. 

 For most species this period includes the first two weeks of July. The 

 position assumed in the process is the one not unusual in Hemiptera, 

 with the caudal extremities together and the heads in opposite directions 

 (Plate XL, 1). The insects are usually very sluggish at this tmie and seldom 

 move unless disturbed. If molested they fall to the ground, not, however, 

 becoming detached from each other. If movement takes place during 

 copulation, the female generally moves forward dragging the male back- 

 ward behind her. The process has been timed from five minutes to one 

 hour in different species. No forms have been observed in flight while 

 in copula. 



During copulation the styles of the male function as clasping organs 

 and the ovipositor of the female is drawn downward and forward. 



Species that have more than one brood a year show more or less well- 

 defined mating seasons during the summer; but in most such species 

 the development of the nymphs is so irregular that the broods overlap 

 and mating may be observed thruout the entire summer and fall. 



