1 4G Miscellaneous. 



forms onto the elms, and was enabled to figure this form and that 

 of the males and females ; but he did not know whence it came, nor 



does any one yet know. 



Bat this present year, vigorously assisted by my young pupil and 

 collaborator, M. Franz Richter, I have examined thousands of the 

 root-tufts of all our wild grasses ; and among numerous examples of 

 Pemphigus and Schizoneura, the history of which will come later on, 

 we found on the roots of Triticum re-pens a colony of Tetraneura with 

 the winged forms, easily recognized by the single vein in their hind 

 wings, whereas the other Pemphigians have two. Placed carefully 

 in tubes, these winged forms furnished sexual forms ; they are there- 

 fore the pupiferous form. We set to work to examine the trunks 

 of the elms growing in the neighbourhood, and under their bark we 

 found the same winged forms busy furnishing the trees with the same 

 sexual forms that the Aphides collected from the grass-roots had 



produced in the tubes. We compared these insects with the figures 

 that Kessler has given of Tetraneura ulrni ; the antennae were diffe- 

 rent, and resembled those of Tetraneura rubra of the emigrant form, 

 i. e. that which quitted the red galls between the 1st and 15th of 

 June. 



Hence there was no more doubt, and the evolution of the red galls 

 of the elm has no longer any gaps. 



The fecundated egg passes the winter under the bark encysted in 

 the body of the female. 



This egg hatches in the spring ; and there issues from it the foun- 

 dress pseudogyne, which forms its gall in April, and surrounds itself 

 in May with a numerous progeny of young animals born alive. 



The whole of this progeny acquires wings and becomes the emi- 

 grant psmdogyne, which flies away and settles itself upon grasses, 

 especially upon Triticum repens. This emigration takes place in 

 June. 



Here this form produces living young, which pass to the roots, 

 where they live as gemmiparous pseudoyynes, continue wingless, and 

 deposit in July and August living young, which are destined to 

 acquire wings. 



In fact, in September and October, this fourth form, which is the 

 pupiferous pseudugyne, issues from the ground in the winged state, 

 and returns to the trunks of the elms, where it produces sexual 

 individuals, which copulate^ after which the female goes to hide 

 herself and die beneath the bark, retaining in her body the single 

 fecundated egg, for which the dried skin of the mother forms a 

 double envelope. 



Each phase, even the sexual, undergoes four moults before becom- 

 ing capable of giving origin to the succeeding phase by gemmation, 

 or of copulating. Including the sexual forms, therefore, this insect 

 presents twenty-four different forms (sixteen in the larval or pseudo- 

 gyne state and eight in the sexual). These forms are in general 

 easy to distinguish by the number of joints in the antennae, which 

 vary from four (in the founders) to five and even six in the winged 

 forms. — Compter Bend's, December 4, 1882, p. 1171. 



