Results of Crossing Euschistus variolarius and Euschistus servus with reference to the Inheritance of an Exclusively Male Character

Katharine Foot, E. C. Strobell
1914 Journal of the Linnean Society of London Zoology  
338 MISSES K. FOOT AND E. C. STROBELL: RESULTS OF in our laboratory, aiming to learn to raiee these bugs with as low a death-rate as possible, and it was not until after three years of experimenting that we fclt it would be safe to attempt to cross two or more of these species. The three most troublesome problems in this work were to provide the proper food, to usc cages well adapted for cleanliness and observation, and to maintain the right degree of moisture. The bugs must have not only
more » ... have not only abundant food, but it must be fresh and clean, and these conditions can be successfully met only by f'rcqiiently transferring the insects to clean cages with fresh food. This slioultl be done at least every third day, or, better still, every second day. Wc were forced to do this work ourselves, for raising the nymphs demands such delicate care that we were unable to entrust it to an assistant. It proved to be an arduous task during part of the breeding season, when, in our experirncnts, we found it necessary to change the food for more than 30 cages each day. The cages we used for the adult bugs were glass dishes about 6 inches in tliametcr and 3 inches deep. The covers were of coarse brass wire mesh, carefully designed to prevent the possihilitay of the tarsi of the bugs being caught at any point where the brass cover comes in contact with the glass dish (text- fig. 2 ). Until we were able to design these covers the bugs were Fig. 2. Cage designed to prevent the insecta frbm catching the tarsi at the point of contact between the glasR dish and the metal top. The spaces marked A and H nre large enough to allow the legs to move about freely, but are too small to admit any part of the body. frequently mutilated, for if the tarsus is caught, the entire leg of the bug is sacrificed, for the leg always gives way at the proximal end of the femur. Such mutilation apparently does not seriously interfere with the functional activity of the bugs, for in one case a female that had lost three legs continued to mate and lay eggs quite normally. The greatest danger lies in the fact that a bug in this mutilated condition cannot always regain its normal position if it has, by chance, dropped on its back, for in this position even the adult bugs frequently die in a few hours. The food chosen for our experiments was wheat and orchard grass while i:ROSSINCi EUSCHISTUS VAIlIOLARIUS AND EUSOHI8TUS SERVUS. LI". J0URN.-ZOOLOQY, VOL. XXXII. 29 PHOTO 6. One of the two male E. uariolatdus from the same deposition of eggs from which we misod the three females for crossing with E. servus : see page 342. PHOTO 7. l'wo male specimens of the F, hybrid genei-ation. These bugs were killed August llth, 1912, and their testes dissected out and mounted for cytologicnl study. PHOTO 8. Two male specimens of the Fl hybrid generation. Killed August 28th, 1912. PHOTO^. The male of the first pair of F1 hybrids. The F, males from this pair of hybrids are shown on P h t e 29, photos 17-2h. 8ee Record IV. nnd page 346. PHoro 10. The male of the third pnir of Fl hybrids. The Fz males from this pair of hybrids are shown on Plate 31, photos 33-41. See Record VI. and page -347. PHOTO 11. The male of the fifth pair of F, hybrids. The Fz uiales from this pnir of hybrids are shown on Plate 28, photos 16 and 16. See Record VIlI. nud p q e 347. PHOTO 12. The male of the fourth pair of F1 hybrids. The F2 males from this pair of hybrids are Rhown on Plate 32, photos 42-48, See Record V11. and page 347." PHOTO 13. The male of the sixth and seventh paire of El hybrids. The F, males f r~~n i the sixth pair nre shown on Plate 32, photos 49 , P: 60, and the Fz males from the seventh pair are shown on Plate 33, photos 61-67. See Records IX. and X. and page 349. PHOTO 14. The male of the second pair of Fl hybrids. The F, males from this pair are shown on Plate 30, photos 28-32. See Record V. and page 346. PHOTOS 16-16. Four F2 male8 from the fifth pair of F, hybrids. 8ee photo 11 for the male of this pair of hybrids, Record VIII. and page 347. PLATE 29. PHOTOS 17-26. Forty-three F2 males from tho first pnir of F1 hybrids. &e photo 9, Plate 28, for the male of this pair of hybrids, Record 1V. and pnge 346. PLATF. 30. PHOTOS 20-32. Thirty Fz males from the second pair of F1 hybrids. See photo 14, Plate 28, for the male of this pair of PI hybrids, Record V. Rnd p~g e :{do, PLATE 31. PHOTOS &9-41. Fortyeight Fa males from the third pItir of F, hjbrids. See photo 10, Plate 28, for the male of this pair of hybrids, Record VI. rnd pnge 317. PLATE 32. PHOTOS 42-48. Twenty-seven FZ males from the fourth pnir of F, hybrids. See photo 12, Plate 28, for the male of this pair of hybrids, Record VII. and page 347. PHOTOS 49-60. Six F 2 males from the sixth pair of F1 hybrids. See photo 13, l'late 28, for the malo of this pair of hybrids, Record IX. and p q e 349. PLATE 33. PHO~OS 61-67. Thirty-two F2 males from the seventh pair of PI hybrids. See photo 18, Plate 38, for the msle of this pair of hybrids, Record X. and page 349.
doi:10.1111/j.1096-3642.1914.tb01461a.x fatcat:gx5vw6btnvcabnzaupfqe2ttd4