70 DAVENPORT ACADEMY OF NATURAL SCIENCES. 



This is the second American species of the spotted-face groujj so 

 common in Europe, and represents the section in which the nerves 

 are concolorous with the elytra, while punctifroiis represents the col- 

 ored nerved section. The spots on the male face are very variable, 

 sometimes covering half the surface and again nearly wanting. The 

 three males from New York are of this type, the spot on the propleura 

 also wanting, as it is in a few of those from Iowa. A damaged female 

 from Denver, Colo., is also apparently of this species. 



Idiocekus alternatus Fitch. (Plate II., Fig. i.) 



This common species is slightly over one fifth of an inch lung with 

 a broad head curving around the pronotum. The middle bears a 

 large reddish-brown blotch, just outside of which, on top, there are 

 two small black spots on a yellow band that extends to the eyes. The 

 pronotum is reddish-brown and usually there is a white stripe down 

 the middle. The wings are partly transparent, tlie veins being dark 

 in some places and light in others, alternating, a light spot near the 

 center of the median line. 



The eggs are about one mm. long by about one fifth of a mm. wide, 

 cylindrical, slightly curved, tapering gradually to a point at one side 

 of the smaller end and cut off obliquely to an obtuse point on the op- 

 posite side at the large end. They are deposited in the young wood, 

 near the tip of a branch, usually close to a bud, sometimes singly, 

 more often three or four near each other. In either case the twig 

 would enlarge at the Sfjot and finally burst open and show the end of 

 the egg in the seam. If many eggs were dejjosited in a twig, as was 

 the case in the cage experiments, it usually died, while if only a few 

 were deposited in a place, as was the case in the field, it sometimes 

 continued to grow, though weak and distorted. The final result on 

 the trees under observation was that over one third of the branches 

 had their tips killed back or distorted, usually the main stem and 

 larger branches being worst affected, [)rohal)ly owing to their more 

 rapid growth in the spring, offering a more fnoraMe place for depo- 

 sition than the slow-growing side branches. 



The larv?e are brownish with light rings or greenish with dark ones 

 according to the amount of exposure of their jjosition, in either case 

 closely imitating the bark upon which they rest The dark rings 

 are made up of about twelve hair-bearing spots on the hind margin of 

 each segment. 



