93 



them than on the special leaf figured. They grow with astonish- 

 ing rapidity, so that one day they are scarcely noticeable, while in 

 a few days they are large. They are usually more or less colored 

 red or brown, and I think the insects, as do most of the plant lice, 

 prefer young trees to old ones. This species was first studied and 

 describeil by Dr. Fitch in his Fifth Report, as New York Ento- 

 mologist, but Dr. Fitch's account is by no means complete and has 

 since been supplemented notably by Dr. Riley, whose figure is 

 reproduced in Ofi. The egg, figure (JG />., is placed in the crev- 

 ices of the bark, and like that of the Schizoneura, is more or less 

 protected bv the dry skin of the insect which produces it. It is a 

 very minute, smooth, vellowish brown body, and remains through 

 the winter, hatching in the spring into a " stem mother," a dark 

 greenish, or olive object which creeps over the twig until it reaches 

 the twigs where the unfolding leaves attract it. To the lower side 

 of these leaves the little insects attach themselves, thrusting 

 their beaks into the soft pulp, ami a gall soon begins to form. On 

 the under side of the leaf the opening is a mere line or slit, hardly 

 as conspicuous in many cases as in the figure, but the swelling of 

 the upper surface is very obvious, being half an inch or more high 

 and twice as long. At first the galls are mere linear elevations, 

 the cockscomb-like form does not appear till later. In the early 

 stages of the growth of the gall the originator of the summer's brood, 

 the louse which hatches from the winter egg inhabits it as a domicile, 

 but ere long, as the gall changes the occupant also changes, molting, 

 growing lighter in color, and secreting finally a whitish chafi'. As 

 the gall reaches its full size the insect produces young, and this 

 continues until the gall is full and sometimes crowded, and on pull- 

 ing apart the sides of the slit on the under side of the leaf, they 

 may be seen, little mouse colored or light gray objects of tlie form 

 off. figure 60. This is about the last of June in this region. 

 Honey dew is produced at this time, tliougli in less abundance 

 than by some other species. In time the lice become of the form 

 shown at d. and finally, when. fully mature like, c. figure 6G. In 

 the young of this generation the color is light greenish or yellow- 

 ish green, but by the time the winged siate is reache<l the color 

 has become dark olive. Until the winged, perfect stage is reach- 

 ed the gall is the sole habitation of tlie insects, but when thus ma- 

 ture they leave it, and so far as is yet known, all of tiiis generatit)n 

 are females and produce eggs. The galls here are niostly empty 



