562 



NEW YORK STATE MUSEUM 



annulets ; feet clear, no marks ; color paler, clearer greenish yellow than 

 before, tracheae very distinct, white ; annulets very obscure ; anal prongs 

 with a very faint blackish shade, a few setae on anal plate. 



Cocoon. At first pale yellow, later brown, opaque. The adult female 

 is about \{^ of an inch long, light yellow, marked with darker and with 

 brownish antennae. The male is a little smaller, black, and marked with 

 yellowish red. 



Bibliography 



1895 Dyar, H. G. Am. Ent. Soc. Trans. 22 : 302-3 



1896 Marlatt, C. L. U. S. Dep't Agric. Div. Ent. Tech. Ser. no. 3, p. 69-70 



Pteronus odoratus Dyar 

 This species lives on willow and has been taken at Ithaca N. Y. The 

 eggs and larval stages are characterized by Dr Dyar as follows : 



Eggs. Laid in masses on the underside of a leaf, on the surface with- 

 out any saw cuts. The dried, empty skins measure .8 x.4 mm. 



First larval stage. Head .3 mm wide, rounded, shining black as in 

 the next stage. 



Second stage. Larvae eating holes in the leaf, near the eggs. Head 

 rounded, full at vertex, black ; width .5 mm. Body held S-shaped ; thoracic 

 feet blackish. Segments annulate shining greenish yellow, pale ; the two 

 rows of sub ventral tubercles visible, smoky ; none seen dorsally. Anal 

 plate small, black. 



Third stage. Head as before; width .7 mm; anal plate and spines 

 black. Lateral and subventral tubercles blackish ; subdorsal black spots 

 faintly indicated. Body light green ; joints 2, 12 and 13 posteriorly yellow- 

 ish. On approaching a group of these larvae on a tree, their peculiar odor 

 is very obvious. 



Fourth stage. As in the next stage, except that the black markings 

 are smaller. Width of head i mm. 



Fifth stage.. Head well rounded ; clypeus large, quadrate, smooth, 

 shining black, tljie sutures and antennae honey-yellow; width 1.4 mm. 

 Body normal for Nematus, terminal segments somewhat swollen. Thoracic 

 feet large, abdominal ones present on joints 6-1 1 and 13 (20 feet), the last 

 pair small. Five medioventral eversible pale yellow scent glands behind 

 the feet on joints 6-10. These function in the normal position of defense 

 of the larvae when the abdomen is held up in an S-shape. A black anal 

 plate with a pair of terminal spines. Segments 4-5 annulate, smooth, 

 slightly shining, the tubercles obsolete dorsally, but represented laterally 

 and subventrally by large, smooth, rounded, shining black prominences, 

 largest subventrally. A dorsal and subdorsal row of round black spots with 



