Aug. ai, 1916 Life-History Studies of Cirphis Unipuncta 809 



0.25 mm., of abdominal segments 0.28 mm., width of head 0.35 mm. Just before first 

 molt, length of body 4.02 mm., width of prothoracic segment 0.464 mm., width of 

 abdominal segment 0.474 mm., length of cervical shield 0.310 mm., width 0.116 mm., 

 width of head 0.35 mm., length of cephalic hairs 0.155 mm., abdominal hairso.080 mm. 



Second instar (immediately after first molt). — Head very pale, shining trans- 

 lucent, and with a very faint tint of raw sienna; no apparent reticulate markings 

 such as appear in later instars; tips of mouth parts brownish to black. Ocelli black 

 and arranged as in the first instar, but more prominent and not so closely placed. 

 Cervical shield shining, translucent, and inconspicuous, and thoracic legs faintly 

 dusky translucent. Ground color of anterior half of body pale green, of the posterior 

 half whitish and with stripes as in preceding instar, but the darker lines more of a 

 yellow-ocher color. Ventral surface whitish or greenish white. Pseudo and anal 

 legs pale translucent. The fine hairs covering the body are whitish and placed on 

 rather conspicuous black tubercles. 



Just before the second molt, the head a shining, light raw umber; mouth parts 

 darker. The ground color of the prothoracic segment whitish, due to the head of the 

 third-instar larva, which is plainly visible through the translucent skin. Body 

 gradually narrowing to anal segment. Otherwise similar in markings to the recently 

 molted second-instar larva, except that the legs are slightly darker, and the lowest 

 brown longitudinal line is paler, tending to yellowish orange. 



Measurements, average of two individuals, as follows: Recently molted larva, 

 length of body, 3.10 mm., width of prothoracic segment 0.531 mm., width of proanal 

 segment 0.368 mm., width of head 0.58 mm., length of longest cephalic hairs 

 0.348 mm. 



Second instar (just before second molt). — Length of body 6.15 mm., width of 

 prothoracic segment 0.71 mm., abdominal segments vary in width from 0.928 mm. 

 for the first abdominal segment to 0.74 mm. for the proanal segment; width of head 

 0.56 mm. 



Third instar (just before third molt). — The head shows the reticulation or brown- 

 ish mottlings illustrated by Forbes. 1 Prothoracic segment transparent, the pale 

 reddish brown reticulations and ocelli on the head of the fourth-instar larva plainly 

 visible beneath. Body markings as in preceding description, excepting that the 

 second dorsal brown band has broken into two brown bands and one whitish band; 

 the third brown band has a paler more or less conspicuous line along its median; the 

 brown band at base of legs almost obliterated; the longitudinal stripes become very 

 faint at the anterior and less so at posterior end. The general color of the body is 

 greenish at anterior end and cream tinted posteriorly. Ventral surface greenish 

 white. Body hairs whitish, except those on dorsum, which are blackish. First pair 

 of abdominal legs now fully developed. Qthenvise as in previous instars. 



Measurements, average of two specimens, as follows: Just before third molt, length 

 of body 10.35 nam., width of prothoracic segment 1.26 mm., of anal segment 1.05 mm., 

 of head 0.95 mm. 



Fourth instar (just after third molt). — Head pale umber with the reticulated 

 markings of raw sienna, as in third instar, but more prominent. General color of 

 body Nile green, paler posteriorly. The longitudinal stripes as in preceding instar, 

 except that lines below the line of spiracles have become entirely obliterated, the 

 color below the spiracles being whitish green to Nile green. The dorsal lines are 

 inconspicuous or indistinct at their extremities. Otherwise as in preceding instars. 



Fourth instar (just before the fourth molt). — Head pale translucent with reticu- 

 lated areas of dusky brown, darker than earlier in instar. The prothoracic segment 

 swollen, showing head of larva of fifth instar; a light raw sienna, the reticulated mark- 



1 Forbes, S. A. A monograph of insect injuries to Indian corn. Part II. 23d Rpt. State Ent. 111., p. 

 84, fig. 63 b. 1905. 



