OF THE STATE ENIOMOLOGIST. 



of two minutes. Issuing from the mouth of the gall, these young lice 

 scatter over the vine, most of them finding their way to the tender 

 terminal leaves, where they settle in the downy bed which the 

 tomentose nature of these leaves affords, and commence pumping up 

 and appropriating the sap. The tongue-sheath is blunt and heavy, 

 but the tongue proper — consisting of three brown, elastic, and wiry 

 filaments, which, united, make so fine a thread as scarcely to be visi- 

 ble with the strongest microscope — is sharp, and easily run under the 

 parenchyma of the leaf. Its puncture causes a curious change in 



the tissues of the leaf, the 

 growth being so stimulated 

 that the under side bulges 

 .^and thickens, w hi 1 e the 

 ]\ down on the upper side in- 

 creases in a circle around 

 the iouse, and finally hides 

 and covers it as it recedes 

 more and more within the 

 deepening cavity. (3) Some- 

 times the lice are so crowd- 

 ed that two occupy the same 



TvPE Gall.ecola:— (7, /v, newly-hatched larva, veutrnl and S^^ll- I^ frOlll the prema- 



dorsal view; c, egg; d, Bcotiou of gall; c, swelling of, j i.i f ii, i 



tendril;,/, ;?,/«, mothei-gaU-lous&-lak'ral, doTS;a and ven- ture death Ot the lOUSO, OF 



tral views; i, her anfeuna; j, her two-joint<'d tareus. 



Natural sizes indicated at sides. Otlier CaUSC, the gall be- 



comes abortive before being completed, then the circle of thickened 

 down or fuzz enlarges with the expansion of the leaf, and remains 

 (Fig. 4, c) to tell the tale of the futile effort. Otherwise, in a few 

 days the gall is formed, and the inheld louse, which, while eating its 

 way into house and home, was also growing apace, begins a partheno- 

 genetic maternity by the deposition of fertile eggs, as her immediate 

 parent had done before. She increases in bulk with pregnancy, and 

 one egg follows another in quick succession, until the gall is crowded. 

 The mother dies and shrivels, and the young, as they hatch, issue and 

 found new galls. This process continues during the summer until the 

 fifth or sixth generation. Every egg brings forth a fertile female, 

 which soon becomes wonderfully prolific. The number of eggs found 

 in a single gall averages about 200; yet it will sometimes reach as 

 many as 500, and, if Dr. Shimer's observations can be relied on, it may 

 even reach 5,000.* I have never found any such number myself; but, 

 even supposing there are but five generations during the year, and 



* Practical Etitomologist, vol. i., p. 17 



