CROSSING EUSCHISTUS VARIOLARIUS AND EUSCHISTUS SERVUS. 343 



As none of these bugs bad mated again by May 26tb^ and the males 

 seemed less vigorous than some wild specimens we had received from North 

 Carolina two days before, we decided to take the live male servus from Cage 2, 

 and replace them with three of the wild specimens just received from North 

 Carolina. Three of the five male scn'vus that were taken from Cage 2 at this 

 time are shown on PL 28. photo 5, and as all five came from the same 

 batch of eggs, these three specimens will serve to demonstrate the species. 

 Each of the three males selected from the wild specimens (to replace the 

 five that were raised in the laboratory) had just mated for several hours 

 with its own species. One was put in Cage 2 May 26th, one on May 27th, 

 and one on May 28th. The next morning at 5 o'clock a pair was found 

 mating, but they separated before we could isolate them. Later in the 

 same day the same female and, probably, the same male mated again. They 

 were then isolated by being left in Cage 2, while the remaining bugs were 

 transferred to another cage. They were kept isolated in Cage 2 until the 

 female died July 16th. 



Before the breeding season commenced, one of the three original female 

 variolarius had unfortunately been thrown away with the stale food, and we 

 were therefore left with only two of the three original females. One of these 

 was undersize and never mated, though she was in a cage for nearly a month 

 with several wild male servus. 



We succeeded therefore in crossing only one female variolarius ^iih. servus ; 

 but this proved to be a fortunate circumstance, for this pair was sufficiently 

 fertile to give us all the Fi and Fg hybrids that we could possibly care 

 for^ as at the same time we were raising hybrids from a cross between 

 E. variolarius ? and E. ictericus (^ . 



The female variolarius and the male servus in Cage 2 mated again 

 June 11th : they mated 51 hours. This was the last time this pair mated, 

 though the female deposited eggs six times after this mating, while 

 normally eggs are deposited only once or twice between two matings. 



In order to compare the breeding habits of this cross and of the 

 Fi hybrids, with the breeding habits of pure variolarius and servus we will 

 give a brief summary of the data we have collected from our laboratory 

 experiments. 



A more detailed account of some of these experiments is given on pp. 362-70, 

 where we have reproduced extracts from our records of eleven pairs of bugs 

 that were isolated through their entire breeding period. All our experiments 

 'with variolarius and with servus indicate that they are alike in certain details 

 of their breeding habits. Records I. & II., pp. 362-3, give what we believe 

 to be the normal breeding habits of both these species. These records show 

 the approximate number of eggs deposited by one female during the breeding- 

 season, the approximate intervals of time between the deposition of eggs, 

 the frequency of the matings, and their approximate duration. They show 



