December, '15] Leonard and crosey: gonatocerus and idiocerus 543 



Stage II (PI. 30, Fig. 2). Length, 1.98 mm., general color dark brownish to black- 

 ish. A pale yellowish median stripe, varying in width, extends from near the vertex 

 back to the middle of the third abdominal segment. Segments five and six of ab- 

 domen yellowish in center. These yellowish markings vary considerably in extent 

 and distinctness in different individuals. There is also a pale yellowish fine on the 

 head bordering the inner margin of the eyes. Eyes reddish. Antennae pale yellow- 

 ish except basal segment which is blackish. Coxae, trochanters, extreme base of fe- 

 mora and tip of middle and hind tibiae pale yellowish or whitish. Tip and base of 

 fore tibiae and tip of fore femora light brownish. First segment of tarsi whitish or 

 shghtly tinged with brownish; second segment of tarsi blackish; claws Hght brown- 

 ish. 



Stage III (PI. 30, Fig. 3). Length, 2.61 mm., width of head including eyes, 

 .85 mm. In this stage the general color is somewhat Hghter than in the two preced- 

 ing stages and the yellowish median stripe is considerably broader. It varies in 

 extent and width but is usually about as shown in the figure. Head wholly tinged 

 with brownish, with dark brownish or blackish on caudal margin inside eyes. Eyes 

 and antennae as in preceding stage. Legs dark brownish or blackish except for the 

 following parts: coxae, trochanters, extreme base of femora, and tip of middle and 

 hind tibiae and first tarsal segment, pale yellowish; tip of fore tibiae, tip of femora, 

 base of tibiae, center of second tarsal segment, and the claws, hght brownish. Met- 

 athoracic wing-pads extend back to second abdominal segment and mesothoracic 

 wing-pads noticeably produced backward. 



Stage IV (PI. 30, Fig. 4). Length, 3.88 mm., width of head including eyes, 1.57 mm. 

 Markings variable but in general as shown in figure. Paler than in preceding stage 

 being rather hght brownish. Head pale bro"WTaish. Median yellowish area broad 

 on prothorax, narrowing on mesothorax, then wider on metathorax. Laterad of 

 this area on the pro- and metathorax pale brownish, on mesothorax dark brownish. 

 Abdomen with two large yellowish areas narrowly connected on the median line, 

 bordered laterally with dark brownish. Eyes and antennae as in preceding stage. 

 Legs yellowish brown, femora paler at base and tip. Fore tibiae tinged with dusky 

 except at base. First tarsal segment yellowish tipped with dusky; second segment 

 dark brownish or blackish, hghter in middle; claws brownish. Wing-pads extend 

 back nearly to third abdominal segment. 



Stage V (PI. 30, Fig. 5). Length, 4.9 mm., width of head including eyes, 1.98 mm. 

 Head pale brownish. Prothorax yellowish or brownish yellow, hind angles darker; 

 mesothorax brownish except a yellowish median portion and a yellowish spot on 

 either side of this, as shown in figure. Metathorax yellowish in center as in prece- 

 ding stage; wing-pads pale brownish. First two segments of abdomen brownish yel- 

 low, remainder of abdomen yellowish except the lateral margins of segments five to 

 nine which are dark brown and a blackish band interrupted narrowly along the 

 median line and including the posterior two-thirds of segment three and the whole 

 of segment four. Antennae and eyes as in preceding stage. Legs hght brownish; 

 first segment of tarsi yeUowish, second segment at base and tip, and the claws, 

 tinged with brownish. Wing-pads extend back to middle of fourth abdominal seg- 

 ment. 



Until about the fourth stage the nymphs remain feeding on the 

 leaves. In the fourth and fifth stages they are found on the smaller 

 t-^igs resting usually with the head directed towards the base of the 

 branch. In this position they bear a striking resemblance, both in 

 form and color, to the buds of the poplar. 



