10 The Europkan Elm Scale 



slender, moniliform, hairy. Second joint with distal end rounded 

 and club-like, about twice as broad as any other segment. The tenth 

 segment is the shortest, the seventh and eighth are of about equal 

 length. The third is longest, comparing with the tenth as 5 is to 9. 

 The lengths of femur, tibia, and tarsus are as 20, 26 and 9. Plate VIII. 

 After moulting three times within its cocoon and pushing out the 

 east skins through the slit in the anal end, the male emerges. Within 

 its cocoon the male larva has undergone three changes in form, pass- 

 ing through two pupal stages and finally emerging either as an active, 

 wingless male or in the fully -mature winged form. Plate VI. 



THE FEMALE INSECT 



On April 15th, 1907, the first wingless males were observed, and 

 on the same date many newly-moulted female larvae. Such females 

 are brown or olive-brown in color, broader and more flattened than the 

 hibernating larvae. The division into segments shows more distinctly, 

 and in many instances the dorsal surface slopes toward each lateral 

 margin from a faint longitudinal ridge. Under the magnifier the 

 newly moulted females appear slightly pubescent and covered with 

 short, stout bristles, Plate IX. 



Honey dew was first observed on the infested elms on May 1st, 

 when ants and flies were attracted to it in large numbers. 



On May 17th, 1907, a few females now nearly mature were begin- 

 ning their semi-cocoons. These consist of tough envelopes of felted 

 waxen fibers excreted from the lateral portion of both the dorsal and 

 ventral surfaces. The completed semi-cocoon adheres closely to the 

 bark and curls over the dorsal surface of the insect far enough to give 

 it support in its usual inverted position on the underside of the 

 branch. Within this supporting semi-cocoon, the eggs are laid and the 

 young are born. 



The mature females gather together in great numbers on the under- 

 sides of the lower branches where the bark of an infested tree is often 

 covered with them; they are easily seen from the ground, even at a 

 considerable height; for the oval ring of white wax surrounding the 

 lustrous, deep-brown insect is a conspicuous object. On fairly smooth 

 bark they gather in clustered hundreds; but on the rough bark of the 

 smaller cork-elms they occur in irregular clusters and rows between 

 the projecting wings of cork. Not all of them, by any means, are 

 found on the larger and lower limbs; many are to be found on the 

 sides of vertical branches, clusters occur on the lower side of small 

 horizontal limbs, many are scattered throughout the tree in the axils 

 of buds and tiny twigs. In the main, however, and as a general and 



