554: SUMMARY OF CURRENT RESEARCHES RELATING TO 



CEcophyUa smaragdina, was found with eight detilated females and a 

 common mass of eggs and larvae, without males or workers. Gynandro- 

 morphism is reported in a Lasiocampid moth, Metanastria hyrtaca : the 

 wings and antenna on the right side are male, on the left side female. 

 A butterfly {CatopsUia) was seen to be caught and eaten by a Drongo ; 

 four other cases were observed, but without identification of species. 

 These are three examples of the author's interesting observations ; the 

 majority refer to injurious insects. 



Comparative Morphology of Zoocecidia.* — B. W. Wells publishes a 

 paper in which he surveys the known insect and mite galls of Celtis 

 occidentals, a species of hackberry occurring in Ohio and Kansas. 

 The paper has great interest, in that it deals comparatively with 

 practically all the galls on one kind of ])laiit, and with the normal tissue 

 of the plant. A histological description of the gall-bearing parts of the 

 plant in their normal stare is given for comparison with the histology of 

 the galls. The author defines a Zoocecidium as " a hypertrophy (abnormal 

 enlargement of single cells) or hyperplasia (abnormal pi'ohferation of 

 cells) of plants, causally related to certain animal parasites." This 

 definition covers all except those rare cases in which the normal tissue 

 undergoes differentiation without apparent hypertrophy or hyperplasia. 

 The etiological problem is dealt with only indirectly, and it is emphasised 

 that the nature of the stimulus applied by the insect is not known. 

 Experimental studies point to a chemical interpretation (enzymes, etc., 

 secreted by the larva), but the chemical theory is as yet only a necessary 

 inference, and is not definitely supported by experimental evidence. 



There are seventeen known species -of Zoocecidia occuring on Celtis 

 occidentalis, and these belong to four orders of Arthropods : Acarina (1), 

 Lepidoptera (1), Hemiptera (5), Diptera (10). All are heteroplasias — 

 that is. those forms of hyperplasia in which the cells and tissues differ 

 from the normal. All are built up on the basis of the same germ- 

 plasm — tbat of the species of plant in question. The acarinous and 

 lepidopterous galls are "' kataplasmas," those forms of heteroplasias 

 whose cells and tissues do not differ widely from the normal. Each 

 shows specific and characteristic inhibition of differentiation. The 

 hemipterous and dipterous galls are prosoplasmas, or those whose cells 

 and especially tissues differ fundamentally from those of the normal 

 parts. Each of these galls shows definite specificity. In the hemip- 

 terous forms the specific characters are in part related to the plant 

 structure which bears the gall ; in the dipterous galls the specific 

 characters are wholly related to the specificity of the physiological 

 phenomena associated with the species of larva concerned in the 

 development of tlie galls. In the prosoplasmas the tyj^es of cells found 

 are closely comparable to those of the normal plant parts, but the tissue- 

 forms discovered are fundamentally new ; no analogous structure-forms 

 are to be found in the tissues of the normal plant or its allies. In the 

 dipterous prosoplasmas, where the galFs specific tissue /or?« -characters 

 are related to the species of insect, there is an " overlapping " of the 



* Ohio Journ. Sci., xvi. (1916) pp. 249-98 (8 pis.). 



