378 SUMMARY OF CURRENT RESEARCHES RELATING TO 



prophase of the first spermatocytes the accessory chromosome occupies 

 its position attached closely to the nuclear membrane. It does not 

 divide in the first spermatocyte mitosis, but passes over to one of the 

 daughter-cells, being therefore absent in one-half of the second sperma- 

 tocytes. In the second spermatocytes, in which it is present, it divides 

 longitudinally. It becomes concealed for a time among the mass of 

 the chromosomes, appearing again when these diffuse. The idiozome, 

 the mitochondria, the nebenkern are also discussed. J. A. T. 



Biology of Chermes. — H. M. Steven {Proc. Roy. Soc. Edinhnrgh, 

 1918, 37, 356). The genera Chermes s. str. and Cnaphalodes are found 

 to have two separate cycles in Britain : — {a) A cycle of two generations, 

 Fundatrix and Gallicola non-migrans ; and (&) a cycle of five genera- 

 tions, Fundatrix, Gallirola migrans, Colonici, Sexupara, and Sexuales. 

 Whether the cycles are those of separate species or of biological races of 

 one species can only be determined by further research. The non- 

 migrating forms are more serious enemies to spruce than are the migrat- 

 ing forms. The collective damage to larch by Colonici of Chermes and 

 Cnaphalodes, and by Progredieutes of the lattei', is serious in Britain. 

 The author adheres to Blochmann's theory that the spruce was the 

 original host of the Chermesidas, and that the winged forms are trans- 

 ported by the wind to trees of other genera, and there adapt themselves 

 to feeding and breeding, the migration back to the spruce being similai'ly 

 effected. ' " J. A. T. 



Notes on Earwigs. — H. H-. Brindley {Proc. Cambridge Phil. Soc, 

 1918, 19, 167-77). Evidence is submitted that the dimorphism of the 

 forcipes in males of Forficida auricularia is not the result of or influenced 

 by Gregarine infection, as Cliard believed. Notes are made on other 

 parasites besides the Gregarine Clepsidrina ovata, viz. Filaria locustse, 

 the Tachinid fly, Rhacodineura antiqua, in Forficula tomis, scarlet mites, 

 and fungoid parasites. As regards food, it seems established that many 

 garden plants are seriously attacked by earwigs, and that the latter can 

 continue healthy on a purely vegetarian diet. But earwigs sometimes 

 kill and devour other insects larger than ihemselves, besides small insect 

 larvse. Only thirteen species of birds seem to have been reported as 

 capturing earwigs, and most of them as very sparingly. They may be 

 distasteful, and a large number together emit a well-defined odour. 

 Domestic fowls always eat them readily. J. A. T. 



Biology of Phthirus pubis. — G. H. F. Nuttall {Parasitology, 

 1918, 383-405, 9 figs.). The crab-louse appears to be parasitic chiefly 

 on persons leading an active sexual life. So far it has only been twice 

 recorded on another host than man, namely, the dog. It may spread 

 from the pubic and perianal region to other parts, e.g. abdomen, breast, 

 and axilla. It occurs very rarely about the eyelids. The head is rarely 

 infested, because the hairs are too close together. Infestation mostly 

 occurs by shed hairs bearing larvae or adufts. The adults cling con- 

 tinuously to hairs, moving from one to another. The females seem to 

 be more numerous than the males in the ratio of 3 : 1 . A female raised 

 experimentally laid three eggs per day, with a total of twenty-six ; the 



