250 SUMMARY OF CURRENT RESEARCHES RELATING TO 



The males show greater effects from " crossiiig-in " than do the females. 

 It was found also that the size and form of the vestigial wing are 

 affected by high temperature, and the males more easily than the 

 females. Roberts discusses two possible interpretations of the facts : — 

 (1) The increased size and variability of the vestigial wing may have 

 been due to the introduction of modifying factors from the wild stock, 

 these factors acting more effectively when the temperature was higher 

 than tlie normal ; or (2) a gametic contamination may have occurred 

 when the vestigial wing factor came into association with its allelomorph, 

 long wing (or in the association of the developer for wings with the 

 absence of this developer). J. A. T. 



Purple Eye in Drosophila. — Calvin B. Bridges {Journ. Exper. 

 Zool., 1919, 28, 265-305). The character " purple eye " has been very 

 useful as a tool in the study of genetics in the fruit-fly. It is a second 

 chromosome eye colour, very distinctive, completely and constantly re- 

 cessive. Its locus is at the middle of the second cln-omosome, close to 

 black. In the field of mutation purple gave with vermilion the first 

 case in which " intensification," or "' disproportionate modification," 

 was recognized and made use of. It was the first of the class of " dark" 

 eye-colour mutations. It has been of great service in attacking the 

 problems of " inviability," " autosomal linkage," and the analysis of 

 the relation between the physical chromosome and the process of " cross- 

 inff over." J. A. T. 



'ft 



Myrmecophilous Beetle. — A. Gallardo {Phjsis, 1916, 2, 254-7, 

 1 fig.). In the nest of the ant SoJenopsis pyladcs Forel the author 

 found a small beetle, Fustiger elegans Raffray, and a little Hemipteron 

 which was tolerated. The beetle was very carefully treated by the ants, 

 which lick odoriferous hairs bordering the elytra, and carry it in their 

 mandibles when dano'er threatens. J. A. T. 



'&"■ 



Spermatogenesis in Deilephila euphorbise. — J. E. Buder {Arch. f. 

 ZeJJforschung, 1916, 14, 5o pp., 4 pi.). Versou's cell and the cyst-cells 

 are regarded as modified spermatogonia. The last spermatogonia are 

 transformed into spermatocytes at the stage of synapsis, due probably to 

 'the fusion of the chromosomes into a single filament. The conjugation 

 of chromosomes is prepared for by the transformation of the filament. 

 Two dyads result. The first division separates the two halves of the 

 dyads and is equational. The second is a reducing division. There is 

 110 basis in the germinative cells for dimorphism. The existence of a 

 lieterochromosome is doubtful. Much attention has been given to the 

 complicated changes undergone by the mitochondria and to the trans- 

 formations of the centrosomes. J. A. T. 



So-called Hypnosis in Cockroach. — J. S. Szymanski (Arch./. Oes. 

 Physiol., 1916, 166, 528-31). If a cockroach {Periplaneta orientalis) 

 is placed in an unnatural attitude and kept from moving, it passes 

 for a variable period into a state of immobility. Even if it be placed on 

 its back and kept in that position it passes into the state of " animal 



