ZOOLOGY AND BOTANY. MICROSCOPY. ETC. 385 



Oviposition in Ichneumon Flies.* — Iv. Cliewyreuv has experimented 

 with Pimpla instif/utor and other species, to which he gave pupae of dif- 

 ferent sizes, e.g. of Sphinx and of Fien's, some large and some small. 

 The eggs laid in large pupa? are mostly eggs which become females ; 

 those laid in small pupae usually become males. If only large pupae 

 are supplied, the progeny will be almost wholly female ; by supplying 

 only small pupae, the female offspring can be practically eliminated. It 

 appears as if the females, like queen-bees, adjusted thcykind of egg laid to 

 the nutritive conditions available. / 



In another paper t the author refers to parth*nogenetic females. 

 While the fecundated females lay eggs which develop into both sexes, 

 those laid by virgin females produce males only. In the case of the 

 fecundated females, the eggs which produce males are unfertilized eggs, 

 and these are laid in smaller pupaa if any choice is afforded. 



Glands of Dipterous Larvae. ± — D. Keilin finds four kinds of glands 

 with external secretion — salivary, mandibular, hypodermic, and peri- 

 stigmatic — ^and gives a short account of their distinguishing features. 

 Salivary glands are of general occurrence. They have usually one epi- 

 thelial layer, but in Syrphin^e there is an additional fibrillar envelope. 

 The mandibular glands/are only known in the genus Sciarcul The peri- 

 stigmatic glands occur beside the stigmatic tuberclesc;. their secretion 

 keeps the stigmata from getting wet. Hypodermic "glands are known 

 only in few cases, such as larval Tipulids. Their secretion prevents 

 desiccation and also drowning. Some of the- hypodermic glands are 

 scattered cells, others are multicellular and^metameric. Of the multi- 

 cellular glands, some have no common cavity, but intracellular canals ; 

 others have a sac and no intracellular canals. They are absent from 

 the imaa^o. 



Parthenogenesis in a Dipterou^ Insect. §—M. Goetghebuer observed 

 in a closed aquarium three successive parthenogenetic generations of 

 Corynoneura celertpes Win., one of the Tentipedidse. A case of parthe- 

 nogenetic p^edogenesis has been previously observed by 0. v. Grimm in 

 a Chironomid, and similar phenomena have been recorded in regard 

 to Tanytar^us by J. Zavrel. The reproduction of Corynoneura is 

 normally sexual, and the significance of the casual parthenogenesis re- 

 corded is unknown. 



Spermatozoa of Orthoptera.|| — J. Yesely discusses in particular the 

 so-called accessory chromosomes or monosomes of the spermatozoa of 

 Orthoptera. They are usually regarded as sex-chromosomes, and as 

 composed of a compact homogeneous substance. Vesely finds, how- 

 ever, that the monosome has a structure. On the surface of an achro- 

 matic central axis there is coiled a spiral of chromonema, which is 



* C.R. Soc. Biol. Paris, Ixxiv. (1913) pp. 695-7. 



t C.R. Soc. Biol. Paris, Ixxiv. (1913) pp. 698-9. 



: Arch. Zool. Exper., Notes et Revue, No. 1, lii. (1913) pp. 1-8 (4 figs.). 



§ Bull. Classe Sci. Acad. Roy. Belgique, 1913, No. 3, pp. 231-3. 



II Anat. Anzeig., xliii. (1913) pp. 569-76 (4 figs.). 



