ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 41 



From the time the eggs are laid till the flies emerge is about 52 days. 

 Both sexes have a lapping organ, in addition to which the females have 

 a distinct piercing instrument. The " rain-trees " serve to harbour great 

 numbers of resting horse-flies. 



Genitalia of Diptera.* — P. E. Keuchenius has studied Syrphidse in 

 particular. He calls attention to the asymmetrical position of the 

 testes. They are almost invariably invested by a Tunica externa and a 

 T. interna or propria. These investments are continued on to the vasa 

 deferentia. The accessory glands, seminal vesicle, and the ductus 

 ejacnlatorius are minutely described. It is striking that nowhere, 

 around the testes or vasa deferentia or accessory tubes, or beginning of 

 the ductus ejaculatorius, are there muscle-fibres to be found. It is con- 

 cluded that the contraction of the abdomen, caused by the abdominal 

 muscles, together with the muscles of the sacculus ejaculatorius, play a 

 part in propelling the sperm and the accompanying fluid. 



Vesicular Secretion of Malpighian Tubes.f — P. Shiwago describes 

 the process by which vesicular plasmic structures appear on the free 

 surface of the cells lining the Malpighian tubes, and lose their con- 

 nexion with the cells, and fall into the lumen. The detailed structure 

 of the cells after feeding and after starving is discussed, with special 

 reference to the changes in the mitochondria. 



Changes of Peripheral Nerves during Metamorphosis.^ — Sorokina- 

 Agafonowa has studied this in the meal-worm (Tenebrio molitor). The 

 nerve-strand which is seen in the sac-like limb during the pupa-stage 

 shows a definite number of collaterals which abut on the hypodermis 

 and end in bipolar cells ; a single multinuclear cell divides into a group 

 of bipolar cells. The young myoblasts seem to link themselves on by 

 means of amoeboid prolongations to fine threads coming from the nerve- 

 strand. 



Embryonic Malformation in Meal-worm.§ — Jar. Krizenecky de- 

 scribes in Tenebrio molitor two cases of consertio segmenti, where seg- 

 ments are connected in an oblique or almost dove-tailed fashion. It 

 was previously recorded by Megusar in the same animal. It is perhaps 

 of widespread occurrence among larva?. It arises during the period of 

 embryonic development. 



Excretory System of Gryllidse.|| — L. Bordas describes the occur- 

 rence of a collecting reservoir or urinary bladder into which the Mal- 

 pighian tubules open and from which a ureter proceeds to the junction of 

 mid-gut and hind-gut. The minute structure is discussed. The internal 

 epithelium, of the tubules consists of large irregular cells, with large 

 nuclei, and long cilia. The bladder shows a very delicate external 



* Zeitschr. wiss. Zool., cv. (1913) pp. 501-36 (3 pis.). 

 t Anat. Anzeig., xliv. (1913) pp. 365-70. 

 J. C.B, Soc. Biol. Paris, lxxv. (1913) pp. 369-71. 

 § Anat. Anzeig., xlv. (1913) pp. 64-73 (8 figs.). 

 Bull. Soc. Zool. France, xxxviii. (1913) pp. 212-17 (3 figs.). 



