\ <::,.] 11 



Tfftiijomitra in various degrees of development, wiiieli were dwelliiif^ 

 under the protection of a Furmicrt, hwt not oi F. puhcsceiis {wh^c]!! 

 liad previously* observed takinj^ charge of Tettigometra vlrescens), 

 but of a smaller species. The idea occurred to me to sec if there were 

 any similar larva? on the artichoke plants, and, in fact, I found some 

 there, but these were under the protection of a third species of ant, 

 a Myrmica. 



In June I revisited the cardoon plants. The THfigomrircc had 

 considerably increased in numbers, and this time they were guarded 

 by Formica puhescens, which had driven away the smaller species of 

 Formica, which I had noticed there before. Again I noticed that the 

 Tcttigometrte were in various stages of development. 



In July the larvae of Tettigomefra had increased in numbers more 

 than ever, and were si\\\ xindiQY iYio. \)YotQi-\.\ow oi Formica puhescens. 

 The protected individuals showing still in this month various degrees 

 of develo2)ment. This circumstance had led me in the preA'ious year 

 to the conjecture that like the Aphides, the Tettigometrce were capable 

 of parthogenesis ; but this conjecture was erroneous, since I observed 

 this time scattered here and there on the cardoon plants some heaps of 

 eggs of Tettigometra. 



Towards the end of August, revisiting these plants, I was at once 

 struck by several unexpected phenomena. Mixedalong with the larvte 

 of the Tettigometra, which, as is well known, are green, there Avas a 

 profusion of black larva?, differing not only in colour, but also in form, 

 and besides which, they were very sluggish, and with little or no power 

 of leaping. Perfectly intermixed with the Tettigometrce, and living iu 

 the greatest harmony with them, these were also under the protection 

 of Formica pnhescens, to which they exuded from the anus from time 

 1.) lime a drop of saccharine liquid. My first impression was that I 

 had hei-e a singular instance of larval dimorphism ; but, on more mature 

 consideration, and after having duly reflected on the great difference 

 in the form of the body and in their agility, I came to the conclusion 

 that I had before me the larvrc of another s])ecies of CicadeJUna cu- 

 joving, lil<c the Tettiijometrce, the same harmonious relations with the 

 ants. I was not, however, able to ascertain with certainty to what 

 genua these table-companions and allies of the Tettigometrce should be 

 referred. But I noticed several times, and in both the cardoon plants, 

 the presence of adult Cicadellincc, winged, brown, and of comijaratively 

 large size. These had precisely the ap])earance and cdiaracters of the 

 genus Issun, and were in all probability the parents of the black larvaj. 



• nuUcttiiio rlcUa Socicti Ent. Italiana, 18T2, p. 343. 



