95 

 other than the stem-motlicr, for I liavc not been able to get any 

 evidence that they are so and very iinich that they are not. I am 

 also sure that, as has already beer^noticed, the insects after leaving 

 the galls go to the extremities of the branches. However, what- 

 ever steps there mav be which are yet unknown, there are at last 

 ]Droduced wingless females, in which develops a large single e^g, 

 as has been seen. . 



Another species ot aphis, which I have not }'et found in this re- 

 gion, is described by Dr. Thomas, as a new species under the 

 name Calliptenis iclmicola^ Thomas. It mav be confined to the 

 West, but it is very probal:)le that it occurs wherever the elm grows. 

 It is described as "an exceedingly delicate species " of a pale yel- 

 low color. Perliaps the character most distinguishing this species 

 from others is found in the wingless form, in which " along the 

 lateral margins of tlie abdomen, in front and behind the honey- 

 tubes are minute tubercles, each giving rise to a hair ; these tuber- 

 cles are quite distinct, and about one to each segment." Thomas, 

 Trans. Depart. Agricult. Ills., 1878, p. 112. 



A very small species, Pemphigjis u/iui-ftis?/s, W., attacks the 

 upper surface of the leaves of the slippery elm. The adult, wing- 

 ed form is only seven hundredths of an inch long. The color is 

 dark. By puncturing the leaves they form spindle-shaped galls, 

 about an inch long. 



In addition to what has been said concerning remedies, it may 

 be said, that since the aphides and tlieir allies are not leaf-eating, 

 l)ut leaf-piercing and sucking insects, applications of Paris green 

 and the like, which are efficacious in the case of leaf-eaters, are of 

 little use, since these are applied onlv to the surface of the leaves 

 which these insects do not eat and cannot penetrate to the juices of 

 the plant upon which they live. Alkaline washes or such as in- 

 jure the soft bodies of the aphides are of most avail, although the 

 fumigation with tobacco, as florists fumigate their greenhouses, 

 using a tent to cover the trees, could be made useful if trees were 

 not too large as also the use of hydrocyanic acid alreadv mentioned. 

 In no group of insects is it so important that the remedv be applied 

 promptly, for none so soon get beyond the reach of remedies. 

 And wdien once they have thoroughly occupied a large tree it is 

 almost impossible to wholly dislodge them. 



The fourth lamily of plant lice, the Psyllidcc^ needs no descrip- 

 tion here, for, so far as I am aware, none of the insects which it in- 

 cludes infest the elm, at least to any noticeable extent. 



