342 MISSES K. FOOT AND E. C. STKOBELL : RESULTS OF 



hour, grow very unequally, occasionally a few of them being so retarded 

 that they have reached only the third moult at the time the others have 

 completed the fifth moult. Nymphs showing such greatly retarded develop- 

 ment almost invariably die. 



Details of Crossing Euscliistus variolarius ? X EuscMstus servus <^ . 



In November 1911, we placed in the same cage three female variolarius 

 and five male servus, allot' which had recently passed the fifth moult. These 

 eight specimens were kept together throughout the following winter. In the 

 sprino- (May 3rd) one of these variolarius females mated with one of the 

 male servus, this demonstrating the possibility of crossing these two species. 

 This female variolarius was hatched in our laboratory September 11th, 1911. 

 The month before we had collected a few wild specimens of variolarius in 

 Ridgefield, Connecticut, in order to secure young, vigorous bugs to carry 

 throuoh the winter for our crossing experiments, and eggs were deposited 

 several times in this cage. It was from one of these groups of eggs that we 

 secured the three females we used for crossing with servus. There were 

 17 eo-o-s in this group, but only seven of them hatched, this being due, 

 undoubtedly, to their having been deposited so late in the season. Six of 

 these seven nymphs — 2 males and 4 females — were reared to the winged stage, 

 the 5th moult not being completed until October 16th. Three of these 

 four variolarius females were selected to cage with servus, nnd the two 

 variolarius males were killed the fourth day after the fifth moult, and 

 preserved in alcohol, in order to avoid the possibility of any question being 

 raised ns to the identification of the females as pure variolarius. One of 

 these two males is shown on PI. 28, photo 6, and the black genital spot, - 

 distinctive of the species vanolarius, is clearly shown. We believe we gained 

 a great advantage by selecting bugs that hatched out so late in the season, 

 for females which reach the winged stage so late as the middle of October 

 are sure to remain all winter as vigorous sexually immature bugs, thus offering 

 the best possible chance for successful breeding experiments in the spring. 

 The five male servus that were kept through the winter with the three 

 female variolarius, were hatched from eggs deposited in our laboratory by a 

 female servus received from North Carolina the day before, the eggs were 

 laid. A group of 10 eggs was deposited September 17th ; 9 of these 

 hatched and 8 were reared to the winged stage, the 5th moult being, 

 completed October 28th. Five of these bugs were males, and three females. 

 On November 3rd the five males were added to the cage which contained 

 the three above-mentioned female variolarius. In the further description of 

 this cross, this cage will be designated as Cage 2. None of these bugs 

 mated until May 3rd when, as stated above, one pair mated 7 hours (see 

 Record III. p. 364). 



