12 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.60. 



white; the apical joint of the tarsi in some specimens is brownish; 

 wings fuliginous, subhyaline beyond the stigma; venation dark 

 brown. 



Male. — Length 5 mm. The above description of the female applies 

 well to the male. Hypopygidium broadly rounded apically, brown- 

 ish beneath; antennae as in figure 11. 



Redescribed from Dyar's type and other specimens from the loca- 

 tions lirted below, 



Oviposition. — The eggs are laid in two parallel rows of slits one 

 on each side of the petiole. They are 1.5 mm. long and placed 

 directly opposite each other in these rows but each egg has its indi- 

 vidual incision. The incision in deeper and the pocket fuller towards 

 the base of the petiole and the opening only extends over the apical 

 two-thirds of the pocket. 



Larva. — Length of full fed larva 13 mm. Head above, from eye 

 to eye, frons and apices of mandibles blackish; epicranium about 

 frons, below antennae, epistoma, labrum, mandibles excepting apices, 

 and ventral mouth parts, yellowish to pale brown. Body (fig. 58) 

 pale yellow, with subdorsal, supraalar and faint epipleural black 

 spots. Annulet A pale excepting faint subdorsal spots, without 

 prominent areas and with only a pair of small subdorsal spines, an- 

 nulets B and C large and thickly spined, the spines grouped upon 

 slightly prominent areas arranged in a transverse row across the 

 dorsum; annulet D bare, narrow, indistinct, pale, without spots or 

 hairs. Epiproct with a pair of subdorsal blackish spots. 



Cocoon. — The cocoon is translucent, pale brown, thin walled cell, 

 length 10 mm., width 4 mm. : irregularly oval. Spun in rearing on 

 dirt or leaves at bottom or sides of cage. 



Pupa. — Pale, 8.5 mm. long. 



Host. — Populus neltoides (according to material from Chas. R. 

 Ely) and Populus tremuloides (according to Dyar). 



Seasonal history. — Gregarious larvae feeding on more or less of 

 the leaf tissue depending on the size of larva, the younger larvae skele- 

 tonizing while the larger leave only the principal veins. The number 

 of generations a year has not as yet been determined; prepupae and 

 larvae about fullgrown on July 19 became adults between August 

 2 and 7. 



Distribution.— KeenQ Valley, New York (Dyar) ; East River. 

 Connecticut (Ely); Northeast, Pennsylvania (Cushman). 



Genus CLADIUS Rossi. 



Cladius Rossi, Fauna EtrUh-oa. ed. 2, vol. 2, 1807, p. 27. Genotype.— Ten- 

 thredo difformis Panzer. 



On account of its peculiar antenna in the male and because it is 

 represented by such common garden insects the genus Cladius has 



