ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 31 



Seed-infesting Chalcis Flies.* — C. R. Crosby describes tbe minute 

 Hymenoptera, known as Ohalcidoidea. He deals with some which depart 

 from the usual insect-infesting habits of their relatives and are injurious 

 to seeds. The apple-seed Chalcis {Syntomaspis druparum), the sorbus- 

 seed Chalcis {Megastigmus brevicaudis), the rose-seed M. aculeatus, the 

 Douglas fir-seed M. spermotrophus, and others are described. 



Luminescence in Chironomus.f — J.C.Tarnani observed this in the 

 sea of Azov in Ghironomus plumosus and another species, but as it was 

 also seen in moribund specimens he thinks it may have been due to 

 bacteria. Luminescence has been previously reported in G. plumosus, 

 C. tendens, and 0. intermedins, but its nature remains obscure. 



Pulex cheopis in Hamburg Docks. $ — W. Fromme found between 

 January 1 and March 28, 1909, no fewer than 199 fleas {Pulex cheopis) 

 on fifty-one rats and two mice from ships in Hamburg Docks. The 

 importance of this is that P. cheopis carries the plague bacillus. The 

 other fleas found on rats are : P. irritans, P. felis, Ceratophgllus 

 fasciatus, Gtmopsylla musculi, Sarcopsylla gallinacea. 



Nephrocytes and Pericardial Cells of Orthoptera.§ — L. Bruntz 

 shows that the nephrocytes which are able to eliminate ammoniacal 

 carmine are not by any means confined to the pericardial region. The 

 pericardial mass is certainly most important, but nephrocytes may occur 

 in the most diverse places— around the salivary glands, about the fatty 

 body, in the buccal appendages, and so on. 



Nuclear Components in Sex -cells of Four Species of Cock- 

 roaches. || — Max Morse has compared Peripla/ieta americam, Stylopyga 

 orientalis, Blatta germanica, and Leucophsea maderiae. 



An unpaired idochromosome or odd chromosome is present in the 

 male of each of these species, and the spermatogonia possess one 

 chromosome fewer than the oogonia. 



In the spermatogonia the odd chromosome is not cast out into the 

 cytoplasm, as Moore and Robinson state, but passes into half the 

 spermatozoa. There is, however, a plasmosome which stains with many 

 chromatin dyes that is extruded from the nucleus. 



A side by side conjugation (parasynapsis of Wilson) of the chromatin 

 threads during synizesis probably occurs. Two longitudinal divisions of 

 the chromosomes thus formed, take place in the two spermatocytes. 

 Synizesis is not an artefact, but is a process bearing definite relations ro 

 the behaviour of the centrosomes. 



Rabl's theory of individuality and Boveri's " Grundgesetz der 

 Zahlenkonstanz " are true as far as the persistence of the odd chromo- 

 some, from the beginning of the first spermatocyte stages, through to 

 the formation of the spermatozoon, affords evidence. 



* Cornell Univ. College Agric, Bull. 265 (1909) pp. 367-88 (2 pis. and 27 figs.). 

 t Eevue Russe d'Entom., viii. (1908) pp. 87-8. See also Zool. Zentralbl., xvi. 

 (1909) p. 613. 



t Centralbl. Bakt. Parasitenk., lii. (1909) pp. 243-8 (1 pi.). 



§ Arch. Zool. Exper., ii. (1909) Notes et Revue, No. 1, pp. xvii.-xix. 



|| Arch. f. Zellforsch., iii. (1909) pp. 483-520 (2 pis. and 1 fig.). 



