iLntomology of the Illinois River. 245 



'Parasites. — A half-grown larva taken April 18 had a 

 ourious dull surface, and the surface of the last segment 

 was covered with oval white scales of various sizes ir- 

 regularly placed, apparently some kind of a parasite. 



After the two egg masses mentioned above had pro- 

 duced larvae, they were placed in a dry vial, and a little 

 later it became evident that both masses had been para- 

 sitized by Hymenoptera, minute black imagos emerging 

 freely in the vial. An examination of one of the masses 

 showed that'about one half of the eggs had been infested. 

 [Fig. 55, 56.] Examples of the imago were sent to Mr. 

 W. H. Ashmead, who found the speceis to be a new one; 

 ^nd it is described by him as Phanurus tdbanivorus on 

 p. 274. 



Egg mass [Fig. 55]. — Blackish-brown, subconic, with 

 oval base, 10-15 mm. long and 8-10 mm. wide, height 

 5-7 mm.; sides convex or concave, apex correspondingly 

 rounded or pointed; eggs pointing obliquely upward 

 and towards one end, both sides meeting upon that end 

 in a more or less prominent longitudinal crest. The 

 eggs are stacked in four or five tiers, one above another, 

 a,nd gummed together into a firm mass. 



Egg. — Length 2.5-2.7 mm., diameter .4 mm. Dark 

 brown, subcylindrical, ends more or less tapering and 

 curved, surface minutely rugose and subopaque. 



Larva^ newly hatched. —In this stage the lateral areas 

 are sculptured similarh^ to those of the adult, but the 

 dorsal and ventral areas, though shining, are rather 

 6parsel3'' striated. Traces of the dark markings are 

 visible, especially on the posterior segments. 



Lai'va, mature [Fig. 50, 51]. — Length 45—55 mm., di- 

 ameter 6—7 mm. Transparent whitish v.'ith a greenish 

 tint, marked with conspicuous dark brownish or greenish 

 fuscous, paler in younger specimens. 



Lateral prothoracic striated areas less than half as 

 long as the dorsal, striation microscopically fine and 

 opaque or scarcely shining, a small smooth spot on the 



