. Bulletin of the Department of Agriculture. Agriculture; Agriculture. --âa 4 BULLETIN" 766, U. S. DEPARTMENT OF AGEICULTURB. In the description of tlie larva Bouche neglected to speak of a A'ery important point, the anal hooks of the first-stage larvae. This character has been found only in one other tachinid first-stage larva, that of the closely allied genus Dexodes. It is v^ry easy to deter- mine this stage by these hooks and to verify the fact that Comp- silura parasitizes early-stage brown-tail moth larvae in the fall, as has been found from various dissections. Pantel describe
. Bulletin of the Department of Agriculture. Agriculture; Agriculture. --âa 4 BULLETIN" 766, U. S. DEPARTMENT OF AGEICULTURB. In the description of tlie larva Bouche neglected to speak of a A'ery important point, the anal hooks of the first-stage larvae. This character has been found only in one other tachinid first-stage larva, that of the closely allied genus Dexodes. It is v^ry easy to deter- mine this stage by these hooks and to verify the fact that Comp- silura parasitizes early-stage brown-tail moth larvae in the fall, as has been found from various dissections. Pantel describes and illu- trates these hooks in "La ; (Fig. 1.) There are three of these peristigmatic hooks; two prestigmatic and one retrostigmatic. It is with these hooks that he larva attaches itself to the peri- trophic membrane just previous to molting into the second stage. As the larva grows, the molt skins are pushed down on to this fun- nel until just previous to emerg- ing, when the full-grown third- stage maggot breaks loose and forces itself out of the dead host. This is done in the following manner: The anterior end of tile parasite, assisted by the mouth hooks, makes a small opening in the integument of the host and by a gradual process of extending and retracting the anterior part of the body the larva finally suc- If the host ^^i^ft^^il « 4â^-'^'^ \â â 'â ''yâ 'JvfS^^^â ':\'â â i^â â '.'.â :â '^â ':'^i^<iK B. Fig. 1.âCompsilura concinnata: Posterior stigmata and peristigmatic hooks of first-stage larva, a, Prestigmatic lioolis, paired; b, stigmatic plate; c, retrostig- matic hook; d, sensory terminations, finger-like or as punctate areas; AâB, horizontal line along which the skin folds over the stigmata as two grasping ceeds in paSsing OUt. PanteLf^""^ magnified. (Redrawn from -^ ^^^ ^^^^ ^^^ ^p^^ ^ ^^^^^^^^ ^^^ parasite larva will pupate within this, but if not, it will drop to the ground or pupate near the host. The time be
Size: 1882px × 1327px
Photo credit: © Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauth, bookcentury1900, bookdecade1910, booksubjectagriculture
