14 



BULLETIN 964, U. S. DEPABTMENT OF AGRICULTURE. 



EGG. 



Fig. 10. 



Egg cylindrical, roundly pointed at caudal end, broadly truncate at cephalic 

 end. One side decidedly convex, opposite side slightly concave. Chorion smooth, 

 lustrous, pearly white, semitransparent, free from sculpture, except surface of trun- 

 cate end, which is roughly shagreened. Truncate end apparently with a collar, 

 below which the egg is slightly constricted, end ellipsoidal in outline. Dimensions, 

 long diameter, 0.21 mm., short diameter, 0.10 mm. Length of egg, outer angle 0.71 

 mm., length of inner angle, 0.56 mm. Diameter at widest point, 0.20 mm. 



NYMPH. 



Figs. 11-15. 



The nymph resembles the adult in general outline and structure 

 but differs in color, and has, in the place of wings such as the adults 



Fig. 10. — Halticus citri: a, Eggs in alfalfa leaf: 6; egg greatly 

 enlarged. 



Fig. n.—IIaUkus citri: First 

 nymphal instar. Greatly 

 enlarged. 



have, dark-colored wing pads, these being most pronounced in the 

 fifth stage. In the first nymphal instar the body is less robust and 

 of a pale clay-yellow color at hatching which turns to pale green 

 after feeding. During the period from the second to the fifth 

 instars, inclusive, the thorax and abdomen increase in size laterally. 

 The body gradually becomes more robust, and at the fifth instar it 

 has assumed almost the shape and form of the adult. The color of 

 the body varies from a light to a dark green. 



The period of time consumed in the development of the nymph 

 ranges from 10 to 18 days, or an average of 14 days, as shown in 

 Table V. 



FIRST INSTAR. 

 Fig. 11 



Length 0.70 mm., width 0.19 mm. (averageof 6 specimens). Numberof body joints 

 13. Segments of abdomen 10. Head, thorax, abdomen, and all appendages pale clay 

 color. Head as wide as body, as long as wide. Eyes lateral and prominent, oval 

 shaped, with hexagonal facet structure, carmine in color. Beak 0.21 mm. long; three 

 joints, dark at apex. Antennae tubular; composed of four joints, first slightly swollen, 

 length 0.08 mm., second 0.15 mm., third 0.20 mm., fourth 0.25 mm. ; total length 0.68 

 mm. 



