June-Sept., 1919.] DlCKERSON & WEISS : IDIOCERUS COGNATUS. 131 



ing eyes 0.51 mm. Color white. Broadest across the head. Sides 

 of thorax subparallel, slightly widest in front. Basal segments of 

 abdomen slightly broader than posterior portion of thorax and gradu- 

 ally rounding to its posterior end. Antennae from one-third to one- 

 half the length of the body, apical third dark. Eyes prominent con- 

 sisting of numerous ommatidia. Head broadly rounded in front, 

 slightly sinuate just before eyes, front and vertex sparsely covered 

 with fine hair. Thorax one and one-half times the length of the 

 head, segments of equal length, each segment slightly broader at 

 posterior than at anterior end. Abdomen varying in length, about 

 one and one-third the length of the thorax. Dorsal surface of body 

 bearing a number of fine hairs. Hairs on abdomen are arranged in 

 longitudinal rows, four dorsal and two lateral. Legs white, bearing 

 a number of fine hairs. Rostrum extending to metathorax. 



Second Nymphal Stage. — Length 1.6 mm. Width of head in- 

 big eyes 0.7 mm. Somewhat similar to preceding stage. Antennae 

 shorter, head shorter. Thorax twice as long as head. Thoracic 

 segments subequal. Sides of meso- and metathorax slightly extended 

 posteriorly. Abdomen twice as long as thorax. Hairs on body more 

 pronounced. A few specimens show two longitudinal light brown 

 dorsal bands extending from head to apex of abdomen and equal in 

 width to light band between them. 



Third Nymphal Stage. — Length 2.5 mm. Width of head includ- 

 ing eyes 0.9 mm. Somewhat similar to preceding stage.' Antennae 

 shorter, head somewhat shorter and more transverse. Posterior ex- 

 tension of meso- and metathoracic segments more pronounced. Most 

 forms of this stage appear to show some markings varying from 

 traces of light bands on thorax to well-defined dark bands extend- 

 ing from head to apex of abdomen with vertex and portion of front 

 of head, portions of legs and some median spots on ventral surface 

 of apical abdominal segments dark. 



Fourth Nymphal Stage. — Length 3.5 mm. Width of head in- 

 cluding eyes 1.2 mm. Head including eyes slightly broader than 

 thorax. Sides of thorax parallel. Abdomen gradually tapering 

 toward tip. Antennae short, about one-half width of head. Head 

 convex, four times as broad as long, anterior and posterior margins 

 parallel, front and vertex finely pubescent. Prothorax at middle one 

 and one-half times length of head. Mesothorax slightly longer and 



