278 FIFTH REPORT OF THE ENTOMOLOGICAL COMMISSION. 
fully developed nests, from which the larvae have since hatched in great 
numbers. It had previously been found on the elm by Professor Riley. 
M Finding an elm at Normal (seriously infested by this louse, and ap- 
parently upon the point of death from the effects upon its foliage, I 
tried the experiment of applying pyretlirum for the destruction of the 
insect A large branch was dusted with a mixture of one part of 
pyretlirum to ten of Hour, at 9.30 a. m., July 4, and soon after the lice 
began falling from the twigs. At 6 p. m. only a few remained, and by 
8 a. m. of the second day thereafter all had fallen off and were lying 
dead upon the table. Spraying the foliage of these trees with water in 
which pyrethruui was suspended in the proportion of about a table- 
spoonful to a gallon of water would, consequently, in all probability, 
destroy the lice, or at least so effectually check their multiplication as 
to prevent injury to the trees." (Forbes). 
53. Callipterus ulmifolii Thos. 
Occurring on the under side of the leaves of the American elm in May and June in 
Illinois. Closely allied to the European C. quercus, which has also four dorsal tuber- 
cles. 
Apterous individuals. — Tubercular, with capitate hairs, which disappear when the 
insect becomes winged. 
Winged individuals. — Antenna? as long as the body; third, fourth, and sometimes 
the fifth joint slightly dusky at apex ; apical joint a very little longer or shorter than 
the sixth. Wings hyaline, all of the veins, and especially the stigmal vein, subhya- 
line. Dorsum with four long spine-like tubercles on its basal portion, and with vari- 
ous shorter tubercles on the apical portion. Length, 1.77 mm ; to tip of wings, 3.04 mm . 
(Thomas, 3d Rep. Ins. Illinois.) 
54. The elm callipterus. 
Callipterus ulmicola Thos. 
Winged specimen.— Wings exceedingly delicate and transparent, appearing as a 
mere film, even the veins scarcely visible with a common pocket magnifier. When 
seen through a strong niicroscrope the latter are pale transparent yellowish; the 
subcostal much the largest and nearly parallel with the costa, bending slightly in- 
ward at the insertion of the first branch vein, which is farther from the base of the 
wing and nearer the stigma than usual ; it also makes a sharp curve forward toward 
the costa at the base of the stigma; the second vein rises about the base of the 
stigma; it and the first vein loth curve somewhat strongly outward (toward the 
apex of the wiug) at base ; third vein, which is twice forked, arises apparently from 
the stigma, but is obsolete or nearly so at the immediate base. The fourth vein is 
nearly obsolete. When seen under a strong microscope it is represented by a series 
of points : it curves regularly but not sharply. Stigma rather broad, somewhat 
hatchet-shaped, widening towards the apex, with a distinct angle at the point where 
the fourth vein arises. The second fork of the third vein about equally distant from 
the apex and third vein. Posterior wings with two branch veins. Antenna' not on 
a tubercle; about as long as the body: third joint long; fourth about three-fonrths 
the length of the third; fifth fully as long as the fourth, and about twice the length 
of the sixth, which is a little longer than the seventh. The whole antenna is quite 
slender. Honey tubes imperfect iu all the wiuged specimens, but they appear to be 
very short, length not exceeding the diameter. 
