278 FIFTH REPORT OF THE ENTOMOLOGICAL COMMISSION. 



fully developed nests, from which the larvae have siuce hatched in great 

 numbers. It had previously been found on the elm by Professor Riley. 

 '"Fiuding 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 pyrethrum for the destruction of the 

 insect. A large branch was dusted with a mixture of one part of 

 pyrethrum to ten of flour, 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 i^yrethrum 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.— Autennee 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, l.TTtmn ; to tip of wings, 3.04'n"'. 

 (Thomas, 3d Rep. Ins. Illinois.) 



54. The elm callipterus. 



Callipterus ulmicola Thos. 



Winged spedwen.— 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 microscrope 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 both curve somewhat strongly outward (toward the 

 apex of the wing) 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. Autennie not on 

 a tubercle ; about as long as the body ; third joint long ; fourth about three-fourths 

 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 in all the winged specimens, but they appear to be 

 very short, length not exceeding the diameter. 



