311 



quently found infesting- the same plant at the same time, which, how- 

 ever, doe.-^ not indicate dimorphism. 



The same was again brietiy described by Mr. Ashmead in the Flor- 

 ida Dispatch (new series, vol. i, p. 241, July 7, 1882), under the name 

 Aphis ciirnUi, with an account in the same paper for July 27, 1882, of 

 its destructiveness to watermelons in Florida and Georgia. 



In 1883 Professor Forbes described and figured this species again in 

 the Twelfth Report on the Noxious and Beneficial Insects of the State 

 of Illinois, in an article on the "Melon Plant Louse" (pp. 83-91), under 

 the name of Aphis cucumeris, stating that it had first been noticed by 

 Prof. Cyrus Thomas in 1880, when it was reported to him as doing 

 much damage to nutmeg muskmelons and cucumber vines, and that in 

 some instances it had almost entirely destroyed fields of vines in 

 southern Illinois. 



It was reported by Professor Forbes as having made its appearance 

 in 18S1 in great numbers in the cucumber fields at Marengo in north- 

 ern Illinois. He stated, however, that it disappeared before the end of 

 the season without doing grave injury. It appeared again early in the 

 spring of 1882 at Normal and in many other localities of Illinois in 

 overwhelming numbers upon both watermelons and muskmelons, so that 

 vines six to seven feet long were literally covered and killed by it. By 

 the first of July it again attracted attention in large fields of cucum- 

 bers at Normal, spreading raj)idly and arresting the growth of the worst- 

 in fested plants, though where muskmelons and cucumbers grew together, 

 the latter were comparatively uninjured, Avhereas the melons were 

 sometimes completely destroyed. 



What will prove, no doubt, to be the same species, was again described 

 by Prof. C. M. Weed in the Bulletin of the Ohio Agricultural Experi- 

 ment Station (vol. ii, no. 6, second series, no. 13, Sept., 1889, pp. 148-150), 

 in an article on the "Strawberry Root-louse" under the name of Aphis 

 forbesi. In this article Mr. Weed cites an interesting observation on 

 the habits of this sj)ecies, published by Prof. S. A. Forbes iu the 

 Thirteenth Report of the State Entomologist of Illinois (pp. 102-103), 

 as follows: 



lu the latter part of September, 1882, an assistaut, Mr. Garuiaii, observed upon 

 strawberry plants near Centralia numerous clusters of dark-green plant-lice, gath- 

 ered on the crowns and between the bases of the roots, at and just beneath the sur- 

 face of the earth. In November they were still found at the same place and iu the 

 same situation as before. They were all wingless and of various sizes, but most of 

 them adults, actively engaged in oviposition; the eggs, some black, some yellow 

 and freshly laid, being abundant among them. 



In some fields near Centralia half or two-thirds of the stools were occupied by 

 them ; but I was not able, at that late season, to estimate the damage due to them. 



No plant-lice of any species Avere seen upon the strawberry elsewhere in southern 

 Illinois, nor have any been seen there since. Even in these very same fields not a 

 louse of auy sort was discovered the following May, at which time the plants Avere 

 tlioroughly searched for them. 



The same species was also found in the same situation upon plants near Normal, 

 in the latter part of September, a fact sliowing the wide distributiou of this form. 



