ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 375 



appears in a partially grown oocyte as a dark granular mass, which 

 probably represents a differentiated part of the protoplasm. 



In gall-flies the history of the oak-knot gall-fly {Andrkus pnnctatus) 

 resembles very closely that of Copidosoma and Apanteles. The oocytes 

 of the blackberry-knot gall-fly {Diadropkus nebulosus) contain a 

 chromatin body which probably results from the condensation of chromo- 

 somes, as in the other forms described. A conspicuous germ -line 

 determinant is also present near the posterior end. The follicle cells 

 divide by mitosis. The half-grown oocytes of the mealy-rose gall-fly 

 {Rhodites iijnotd) are provided with hundreds of secondary nuclei, which 

 are all situated in a single layer equidistant from the periphery at all 

 points. In younger oocytes t'lese secondary nuclei appear to arise near 

 the periphery from granules which stain like chromatin. These granules 

 may be extruded by the oocyte nucleus, the follicle cells, or the nurse- 

 cells. 



Note on Myrmecophily.* — W. C. Crawley points out that the 

 myrmecophilous beetle Glaviger testaceus is sometimes found resting on 

 the queens in nests of Lasius fiavus, the normal host, but that the 

 queens of L. umbrattis appear to possess a much stronger attraction for 

 them. When a few beetles were put into nests containing L, umbratus 

 queens they clung to them and never seemed to change their resting- 

 place for weeks. It is probable that the parasitic queens {L. iimbrafus, 

 L.fulk/mosHS, a^nd. others) have a body-secretion which renders them 

 attractive to other species of ants and to Myrmecophiles. 



Polymorphism in Insects.!— A. Berlese has made an elaborate 

 analysis of the different forms of polymorphism in insects. He deals 

 first with individual polymorphism (Heteroidia), which may be in the 

 same individual at the same time (asymmetry), e.g. gynandro-morphism, 

 or at different times as in metamorphosis, or between different 

 individuals as in the contrasts of males, females, hermaphrodites, sterile 

 individuals, and young individuals. 



The polymorphism may also be collective (Heterogonia) ; and here 

 Berlese distinguishes between sexual dimorphism, synchronous castes, 

 heterocronous castes, periodic polymorphism with the castes in different 

 surroundings, and permanent polymorphism (for an indefinite time) 

 with the castes or varieties in different surroundings. 



Berlese deals in this paper with individual polymorphism in 

 particular, and illustrates his views with some ingenious diagrams. 

 Polymorphism between individuals affects size, organization, colora- 

 tion, and the like. It points to lability and superfluity. It may be 

 hypertelic, which means transcending the (eutelic) mean, or hypotelic 

 or atelic, which implies the reduction or absence of a feature possessed 

 by the mean of the stock. Individual polymorphism is mainly due to 

 changes in environment, especially in the nutritive conditions. 



* Ann. Nat. Hi.st.,xvii. (191G) pp. 377-8. 

 t Redia, xi. (1916) pp. 211-38 (3 figs.). 



