ZOOLOGY AND BOTANY, MICKOSCOPY, ETC. 115 



Dipterous Enemy of Aphides.* — John J. Davis gives the life- 

 history of Aphidoletus meridionalis Felt, a cecidomyid fly the larva of 

 which is an enemy of many species of aphides. The fly is remarkably 

 prolific, and each larva may destroy dozens of aphides ; it is therefore 

 an insect of great economic importance. The author found it destroying 

 large colonies of Aphis setarise and Hyalopterus pruni on plum. 



The eggs are elliptical oval, chrome-yellow in colour, and measure 

 about • 3 mm. in length by ' 1 mm. in width. They are laid in 

 clusters of from one to twelve on foliage amongst a colony of aphides, 

 or on the back of the aphis, so many as seven having been noted on a 

 single aphis. The female lays more than 100 eggs. On hatching the 

 larva attacks an aphis by piercing its body from beneath, and after 

 sucking the body-fluid leisurely moves to another. After it becomes 

 one-third grown it usually punctures the aphis at one of the articula- 

 tions of the legs. When fully mature it spins a loose cocoon of silk, 

 attaching it to a leaf, or descends to the ground and spins it at or near 

 the surface. The larva very shortly pupates ; the pupa is 2 mm. long ; 

 the pupal stage varies in duration from six to nine days. The adult is 

 a frail midge, the male being 1*4 mm. 'long and the female 1'8 mm. 

 Egg-laying continues for about ten days, the midge living about fourteen 

 days. The life-cycle from egg to adult varies from fifteen to twenty- 

 nine days in length, and there are at least six generations annually. 



Experiments on Mang'old-fly.f — Alfred B. Cameron finds that 

 Pegomyki hyoscyami reared on belladonna will oviposit and complete its 

 life-history on mangolds if belladonna be absent. Specimens reared on 

 mangold-leaves did not oviposit on those of the nearly allied sugar-beet. 

 He also finds that P. hkolor reared on dock does not oviposit and 

 complete its life-history on mangold or sugar-beet. 



Braconid Parasitism. | — Timberlake finds that some beetles may 

 be thoroughly parasitized by the common Braconid, Dinocampus ameri- 

 canus, without fatal results. The larva of the parasite may attain full 

 size and escape, yet the recovery of the beetle may be complete. The 

 vital organs do not seem to be injured, but the depletion of the fatty 

 body or the presence of the exit aperture is sometimes fatal. Yet 

 experiments show that successive parasitism may occur, and more than 

 one generation of parasite pass out from one and the same host. 



Life-histories of Leaf-hoppers. §— Herbert Osborn gives an account 

 of the eggs and nymphs of various leaf-hoppers (Jassida) injurious to 

 grass and grain crops in Maine, and discusses methods of controlling 

 the pests. 



Setal Pattern of Caterpillars. || — A. Schierbeek concludes that 

 a far-reaching correspondence of arrangement obtains between the setse, 



* Journ. Agric. Research Washington, vi. (1916) pp. 885-8 (1 pi.). 

 + BuU. Entomol. Research, vii. (1916) pp. 87-92 (2 figs.). 



X Canadian Entomologist, xlviii. (1916) pp. 89-91. See also Trans. Amer. Micr- 

 Soc, XXXV. (1916) pp. 146-6. 



§ Maine Agric. Exper. Stat., Bull. No. 248 (1916) pp. 53-80 (13 figs.). 

 II Proc. k. Akad. Wetensch. Amsterdam, xix. (1916) pp. 24-38. 



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