408 



the smaller rootlets liad also been devoured, or more or less injured, 

 by tliem. 



The larva (Fig. 48 a) is of a milk-white color, with a prominent black 

 head, and attains a length of about G millimeters. Pupation occurs in 

 an oval cell lined with a few silken tlireads, the cells being formed at a 

 depth of half an inch or less beneath the surface of the ground. The 

 eggs are usually scattered on the ground, but are sometimes deposited 

 in clusters of twenty or more; they are oval, polished, white, and meas- 

 ure about one-tenth of a millimeter in length. 



This species belongs to the genus Sciara as restricted by the German 

 entomologist Riibsaameu in his recent revision of the genera and species 

 belonging to this group (Berliner Eutomologische Zeitschrift, ^lay, 

 1894, pp. 17-24). The present species differs from any of those hereto- 

 fore described in several important particulars, notably in the coloring 

 of the thorax and pleura : and in the belief that it is as yet undescribed, 

 is duly characterized herewith : 



Sciara tritici n. sp. 



Male. — Auteuiiiv two-thirds as long as the body, bhick, the first two joints lulvous; 

 head black, the face fulvous; palpi brown. Thorax dorsally fiilvons, the pleura 

 brownish, marked on the lowest third Avith a whitish vitta, also with a whitish spot 

 below the humerus. Abdomen reddish-brown, basal joints of hypopygium each 

 bearing a stout macrochseta at the tip of its inner side, the apical joints bearing 

 several short, claw-like processes on the apical third of the inner side and at the 

 tip (Fig. 48). Legs testaceous, front coxjb two thirds as long as their femora. 

 Wings iridescent, grayish hyaline, the veins brown excepting tbe fourth which is 

 very faint, the forks more distinct but much less robust than the other veins; costal 

 and first veins bearing microscopic siiines on nearly their whole length, the second 

 vein also spinose beyond the small cross-vein, the others bare: costa straight or 

 gently convex on the basal half; first veins extending slightly beyond the middle of 

 the wing, its last section half as long as the preceding; fourth A'ein forking far 

 beyond the tip of the first, the distance about equaling four times the greatest width 

 of the marginal cell; anterior fork of fourth vein seven-nintlis as long as the pre- 

 ceding section of that vein forking at a distance from its base equal to slightly over 

 twice the greatest width of the costal cell. Halteres yellow, the knob brownish. 



Female. — Same as the S except that the antenujc are only half as long as the body. 

 The last joint of the ovipositor is slightly longer than wide. 



Length, 1.8 to 2.5™"". Teu males and fifteen females. 



NOTES ON PARIS GREEN. 



By C. L. M.VRLATT. 



Paris green is the most useful and valuable of the arsenicals used as 

 insecticides. As is well known, its action is more rapid and effective 

 than that of London purple, and having a definite chemical composi- 

 tion it ought uot to be subject to variation in the amount of the active 

 agent, arsenic. Its use as an insecticide has enormously extended of 

 late years, and upward of 2,000 tons are annually employed in the 

 United States, besides 400 tons in Canada. The chief difficulty m 



