424 



PSrCHE. 



[Sejitember iSq6. 



LIFE HISTORY OF ICHTHVURA STRIGOSA GROTE. 



BY HARRISON G. DVAR, NEW YORK CITY. 



Larva. Closely like that of /. apicalia' 

 much paler in the early stages, darker in the 

 last stage, the head black, not brown, the 

 body of a dark purplish color, but marked in 

 exactly' the same pattern as /. aficalis. 



Eggs. Laid in patches of 25 to 50 on the 

 under side of leaves of Popnlus treinnloides 

 at Jefferson Highlands, N. H., in June. 

 Somewhat conoidal, not exactly hemispheri- 

 cal, when fresh not shining bright emerald 

 green, later of a purplish color, the heads of 

 the enclosed larvse showing as black spots at 

 the vertices; shell milky white ; reticulations 

 evident, neat, but narrow, almost linear and 

 rather small, hexagonal with rounded angles, 

 a small, better marked area at the vertex. 

 Diameter, S mm. ; height, 5 mm. 



On hatching the larvte do not run off as 

 apicalh does, but begin to form their houses 

 without wandering. They are less solitary 

 in habit than apicalis. 



Stage I. Head rather cordate, mouth 

 pointed; shining black; width about 4 mm. 

 Body slightly flattened, grayish white, the 

 slight elevation on joint 12 vinous brown and 

 all of the sides thinly mottled with the same 

 color; cervical shield black, anal plate vinous ; 

 thoracic feet black. The vinous on the sides 

 is very obscure, being most pronounced in a 

 narrow subdorsal line. Seta; single, long, 

 dark at base, normal, vi absent, though rep- 

 resented by a slight tubercle without seta; 

 leg plate distinct; on thorax no subprimary 

 setse, vi with two hairs; the two lower setae 

 of cervical shield detached. Skin covered 

 with cuticular points. 



Stage II. Tubercles converted into 

 small warts \vith a few secondary hairs from 

 the skin besides. On abdomen normal, vi 

 present; on thorax the seta; of i and ii unite 

 to form three warts, the upper one small. 

 Head slightly bilobed, shining black; width. 



7 mm. Body pale yellow dorsally on joints 

 3 to 12 with three faint purpli^h lines: cervi- 

 cal shield and anal plate smoky; a central 

 purple spot on joints 5 and 12, the latter 

 joint a little enlarged. A sub-dorsal, purple- 

 brown mottled line and faint mottlings on 

 the sides; feet and leg plates dusky. Hairs 

 pale, some of them long. Later the pale 

 parts predominate so that the body appears 

 multilineate with pale, the warts yellow. 



Stage III. Width of head i.t mm. 



Stage IV. Head bilobed, shining black 

 with many soft white hairs; medium suture 

 deep, clypeus small, triangular, sunken below 

 the bulging lobes; width, 2 mm. The bod^' 

 appears as before — a whitish ground, trav- 

 ersed by faint triple dorsal, triple approxi- 

 mate lateral and double stigmatal broken, 

 narrow, purplish brown bands, the dorsal 

 ones fainter than the others. Central dorsal 

 spots behind tubercle i on joints 5 and 12, 

 brown, no humps; warts all yellow. Pri- 

 mary and secondary hairs soft, pale, not 

 long. 



Stage V. Head black, the broad, high 

 clypeus pale, scarcely sunken ; width 3.2 mm. 

 Body as before, the dorsal patches on joints 

 5 and 12 much fainter; warts conspicuously 

 yellow. The pale brown mottled lines are 

 broader than the five intervening spaces on 

 each side, mottled, pulverulent on a dirty 

 whitish ground. A single example had the 

 colors brighter, the lines red, "lake red," 

 the three dorsal tainter than the lateral 

 ones; tubercles yellow, the lateral ones giv- 

 ing the appearance of yellow lines alternat- 

 ing with the lateral red ones (as in Dr. 

 Packard's description). Later as the larvze 

 mature the head becomes nearly entirely 

 black, the lines dark dull purple, broad, 

 mottled and freckled, reducing the ground 

 color to narrow irregular pale lines. The 



