INVERTEBRATA, CRYPTOGAMIA, MICROSCOPY, ETC. 781 



abdomen, a bunch of colourless bair-like scales lying in a fold on 

 eacb side of the first abdominal segment ; it could be extruded from 

 the fold by pressure. The aperture has the form of a cylindrical tube, 

 and here a strong musky scent was perceptible, and did not occur 

 elsewhere. The scales are readily visible with the naked eye. 



Spinning Organs of Insect Larvae.* — Dr. Gustav Joseph has a 

 preliminary communication on these organs. He finds, in oppo- 

 sition to Lidth de Jeude, that they are supplied with nerves from 

 the sub-oesophageal ganglia and from the gastric nervous system. 

 When the integument is carefully removed from young larvae in 

 which the fatty body is but slightly developed, it may be seen that 

 between the peritoneal investment of the spinning tube and its 

 glandular cell-layer there is a distinct nervous plexus formed of 

 extremely fine dichotomous filaments which pass in between the 

 gland-cells. 



These spinning organs are developed very early in the course 

 of existence, and commence as a small depression ; this gradually 

 deepens and becomes converted into a tube ; the cells which bound 

 its lumen are at first scarcely to be distinguished from the morpho- 

 logical elements which make up the outermost layer of the general 

 integument. These tubules generally make their appearance before 

 the salivary glands, but this is not always the case. The author, 

 in opposition to Hatschek, woiald regard them as being tegumentary 

 glands, or in other words as being primarily difi'erentiatcd from 

 the integument. They are not to be confotmded with the salivary 

 glands, the function of which is in relation to the ingested nutri- 

 ment ; and they themselves demonstrate their relations to the integu- 

 ment by forming a secretion which hardens on exposure to the air, 

 and has some of the characters of a cuticle. 



As is briefly pointed out, the development of the three constituent 

 parts of the tube — gland, reservoir, and efferent duct — diflers in 

 different species. Further details are promised. 



Parthenogenesis in Halictus.f — The observations of M. Fabro 

 have been chiefly made on Halictus cylindricus and H. sexcinctiis. 

 After a description of the conditions under which he observed the two 

 species, the author points out tliat for this genus there is no "society" 

 in the entomological sense of the word ; each mother cares only 

 for its own larvaj, though the various jiarents unite to form a common 

 liome ; each cell in the gallery is nevertheless the property of a 

 single Halictus. As to the relations of the sexes, wo find that males 

 are very rarely to be detected ; in September, however, they are to bo 

 found in quantity. Beginning, then, with the month of November, 

 wo find females which have evidently been fertilized ; this is easy 

 to understand, but at this ptriod tlio males have completely dis- 

 appeared. The females pass the winter in their cells, and towards 

 ]\Iay they come out and work at their nests. In July, though no 

 males have yet been seen, there is a second generation ; but hero 



• ' Zmil. Anzcig.,' iii. (1S80) p. 326. 

 t ' Ann. Sci. Nat.,' ix. (1880) Art. 1. 



