Alternating generations; a biological study of oak galls and gall flies . Pla-te ni. OaM-Jcli. Jlic. *.-, hth. The Method of Ovipositing, 115 quite evident that the anterior plate remains always afixed point, while on the contrary the posterior plateis drawn alternately up and down. By these simplemovements of the posterior plate, the insertion andwithdrawal of the spiculae are carried on ; the thrustingout of the spiculae is the harder operation, and iseffected by two powerful muscles; while their with-drawal is easier, and requires only one muscle. Theanterior plate remains passive dur
Alternating generations; a biological study of oak galls and gall flies . Pla-te ni. OaM-Jcli. Jlic. *.-, hth. The Method of Ovipositing, 115 quite evident that the anterior plate remains always afixed point, while on the contrary the posterior plateis drawn alternately up and down. By these simplemovements of the posterior plate, the insertion andwithdrawal of the spiculae are carried on ; the thrustingout of the spiculae is the harder operation, and iseffected by two powerful muscles; while their with-drawal is easier, and requires only one muscle. Theanterior plate remains passive during the act of ovi-positing, therefore the seta, which is firmly unitedto it, takes a less active part; it is pushed steadilyforward by the fly and is driven into the canal that hasbeen bored and opened by the spiculae. We must next inquire into the manner in which thegall-fly introduces the egg into the bud by means ofthis apparatus. Hartigs explanation, which has hithertobeen received, was that the extremely ductile egg wasdriven through the ovipositor itself. He thoughtthat th
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectgallsbo, bookyear1894
