CROSSING EUSCHISTUS VARIOLAKIUS AND EUSCHISTUS SEIWUS. 349 



2 P.M. oF the Scame clay the female with the green venter mated with this 

 male, and we transferred the pair to Cage 48. Thus the two females of 

 Cages 46 & 48 were fertilized by the same male, The two grey venter males 

 that had never mated were put back into Cage 36, which now contained these 

 two males and two females, none of which had mated. On August 28th 

 these four l)ugs were killed and preserved. The two males are shown on 

 Plate 28, {)lioto 8. The male that had mated with the two females (Cages 46 

 & 48 = Records IX. & X.) was transferred after each mating from one of 

 these cages to the other during the rest of the breeding season. We hoped 

 we could raise enough offspring from each of these two females for a com- 

 parative study of the transmission of the genital spot through two different 

 females fertilized by the same male. We were, however, disappointed in 

 this, as we succeeded in raising only seven males from one of the two females 

 — not enough to be of value for comparative study. 

 The results, briefly, are as follows : — 



Record IX. (p. 369). Sixth Pair ofF^ Hybrids. — 134 eggs were deposited 

 from August 22nd to September 19th. The pair mated 11 times, and eggs 

 were deposited 10 times, and not oftener than once or twice between two 

 matings. Only 33 of these 134 eggs developed to the point of hatchino-, 

 although a great many more were fertilized, and there was no obvious reason 

 why they did not hatch. Only 13 of these nymphs survived to the winged 

 stage (7 cJ & 6 ? ). Six of the males were photographed and are shown on 

 Plate 32, photos 49 & 50. The male of this pair was killed September 19th 

 and the female September 21st. The male was photographed and is shown 

 on Plate 28, photo 13 (this male fertilized also the female of Record X.). 



Record X. (p. 369). Seventh Pair of Pj Pfyhrids. — 120 eggs were 

 deposited from August 20th to September 8th. The pair mated 8 times, 

 and eggs were deposited 8 times, and in only one instance were they 

 deposited more than twice between two matings. 



104 of these 120 eggs hatched, and 68 of the nymphs were reared to the 

 winged stage (34 (J & 34 ? ) . Thirty-two of these males were photographed 

 and are shown on Plate 33, photos 51-57. Two males died in the cage just 

 after the 5th moult, and were destroyed because the ventral surface was dark 

 and pathological. 



The above summary of the records of the seven Fi hybrid pairs shoM's 

 several features that are apparently typical of this generation of hybrids. 

 These records show further, that if the Fi hybrids can be secured, the F2 

 generation can be obtained in large numbers. The Fi hybrid generation is 

 quite as fertile as the original pairs of either pure variolarius or pure servus 



