12 The Euhopean Elm Scale 



the exceedingly delicate egg-shells, and among them a few eggs. The 

 egg is oblong in outline, pale yellow in color, about one-eightieth of an 

 inch long and half as wide. Upon the drying of the shell or membrane 

 in which it is enclosed the larva within bursts its covering and 

 emerges head first, leaving within the semi-cocoon of the female the 

 delicate egg-shell. As the oviduct opens on the ventral surface of the 

 body near the anal extremity, the newly-hatched larvae find themselves 

 within the semi-cocoon, protected by it and the body of the female. 

 One such egg-laying female, when attached to a glass slip by means 

 of a tiny drop of Canada balsam, expelled four eggs in about twelve 

 minutes ; all of them hatcshed within half an hour. 



THE NEWLY-HATCHED LARVAE 



These are so minute that they would be invisible in bright sunlight 

 if it were not for their bright yellow color. In sunlight they appear as 

 tiny, lemon-yellow specks crawling slowly about on the bark. On 

 June 24th, 1907, many of them had already occupied positions on the 

 leaves. Some were in the groove of the mid-rib on the upper surface. 

 More were to be found, however, on the underside of the leaf along 

 the mid-rib in the axils of branching veins. They were partially con- 

 cealed by the pubescence of the leaf, Plate XIII. On June 26th, the 

 larvae were appearing far more rapidly than they could escape from 

 the semi-cocoon, Plates XI, and XII. On July 2d, 1907, newly- 

 hatched larvae were very abundant. They were still abundant in the 

 semi-cocoons of the females and along the mid-ribs of the leaves on 

 August 9th. Some larvae just out of the egg were photographed on 

 September 16th, 1907. Most of the larvae pass the sununer on the 

 leaves, largely on the under surface, some settle permanently in the 

 axils of the leaves or upon the buds; many remain upon the leaves 

 until they fall in the autumn. 



THE EGG, PLATE XI 



Length, approximately .32 mm. Breadth, .16 mm. Outline an ellipse 

 whose length is to its breadth as two is to one. Color, bright lemon-yellow. 

 Surface smooth and glistening as though viscous at first; becoming wrinkled 

 as it dries and finally bursting a few minutes after it is deposited. Through 

 the superficial Integument the eyes of the larva within are distinctly seen 

 as two black specks. 



Reno, Aug. 12th, 1907. 

 I observed some females laying eggs today. I have seen nothing so 

 far to indicate that the young of this species are born ovovivipacously. The 

 egg Is expelled from the female, and upon contact with the air, bursts and 

 the larva emerges. 



