PROCEEDINGS, 1917. 19 



LIFE STAGES OF ONCOPSIS SOBRIUS WALK 



Egg. — The egg is small and cylindrical, slightly curved, wider at posterior end 

 which is bluntly rounded; pale yellow, with sometimes a slight greenish tint; chorion 

 smooth, shining. Length, .87mm-. 37mm. 



Nymphs. — The different nymphal instars vary considerably as regards color as 

 do also the various individuals of the same instar. They are generally of a yellowish 

 brown tint, some being quite yellow, others very dark brown approaching black. 



First Instar. — General form of body rather short and stout, widest at eyes. Lat- 

 eral margins of thoracic segments almost parallel, abdomen short and flexible, widest 

 at third segment, thence tapering rather buntly to caudal extremity. Head, wide, 

 rounded before eyes; antennae short, swollen at base, tapering to a fine point. Beak 

 attaining the mesothorax. Lateral margins of segments provided with short stout 

 spines. Legs, medium length, rather stout, clothed with minute hairs, evenly placed. 

 General color of newly hatched nymph, light yellow, changing to dark ashy grey or 

 almost black. Eyes dark red or black. Head and thorax dar.< brown. Legs dusky . 

 Length of body 1.06mm. — 1.075mm.; width of head including eyes, .40mm. -.450mm., 

 length .25mm. -.3mm.; length of thorax .35mm.- .40 mm., width .35mm. -.40mm.; length 

 of abdomen .5mm.-. 55mm., greatest width .3mm.-. 35mm. 



Second Instar. — Differs from preceding chiefly in size, color and in the form of 

 the head, which curves up abruptly from eyes, but is somewhat flattened on cephalic 

 margin. General color, dull, dirty yellow with darker markings. Eyes dark red. An- 

 tennae and legs colorless or with a slight yellowish tinge. Length of body 1.45mm.- 

 1.50mm.; width of head including eyes .5mm.-. 530mm.; abdomen at widest point .42 

 mm. -.45mm. 



Third Instar. — Resembles preceding instars in general form, but with last two 

 thoracic segments wider than prothorax and with lateral margins rounded and project- 

 ing distinctly caudad. Color varying from light yellow to brown with darker mark- 

 ings on which are found a number of small blac < circular dots irregularly placed. Length 

 of body .2 mm.-2.15 mm.; width of head including eyes .7 mm. -.75mm.; abdomen at 

 widest point .8mm. 



Fourth Instar. — General form resembling preceding instars but proportionately 

 broader. Lateral angles of mesothorax and metathorax projecting caudad, forming 

 small wing pads reaching to the anterior margins of the second abdominal segment. 

 General color yellowish brown, lighter at the lateral margins, with darter portions ex- 

 tending over greater part of thorax and abdomen, covered with minute blaci dots. 

 Legs light yellow, darker at tips of tibiae and tarsi. Length of body 2.6 mm. -2. 75mm . ; 

 width of head including eyes .95mm-1.05mm. 



Filth Instar. — General form resembling preceding instars, with greater develop- 

 ment of wing pads. General color dark brown to black with lighter markings. Lateral 

 and caudal margins of thoracic segments with a light border. A light colored strip ex- 

 tends along median line of abdomen. Entire penultimate segment of abdomen light 

 yellow. There are two dark slightly raised circular spots on the dorsal surface of the 

 prothorax and mesothorax and two similai oval spots on the head. Length of body 

 3 mm. -3. 15mm.; width of head including eyes 1.4 mm.-1.45 mm. 



Adult. — The following is the description given by Van Duzee* for this species: — 



"Testaceous yellow above, pale straw color beneath, elytra deep fulvous brown, 

 with slight vinous tinge; vertex with an obsolete transverse yellow vitta. Length 

 5mm. 



Face rather convex, closely punctured; vetex with an impressed line above the 

 ocelli and an obscure central ridge; base of the front with a faint yellowish line; cheeks, 

 lorae, apex of the clypeus and all beneath pale straw yellow. Pronotum large, sloping 

 quite strongly toward the head; finely transversely wrinkled and punctured with a 

 calloused area behind the eye. Elytra fulvous brown, commissural nervure obscurely 

 alternated with pale. Wings very faintly smoky, nervures brown, ultimate ventral seg- 

 ment of the female larger than the penultimate, apical margin rounded, notch small." 



Between June 9th and 17th a large number of tiny hymenopterous egg parasites 

 emerged from the infested twigs. These appeared to be the same species as is so com- 

 monly found attacking the eggs of Ceresa bubalus Fab. viz. Polynema striaticorne Gir. 

 The description of this insect as prepared from our specimen is here given as 

 we were unable to obtain a certain determination of the species: 



*VanDuzee, E. P ., Review of N. A. Species of Bythoscopsus, Ent. Amer. Vol. VI, 

 224 (1890). 



