December, '15] LEONARD AND CROSBY: GONATOCERUS AND IDIOCERUS 545 



Described from thirty-four adult specimens — thirteen females and 

 twenty-one males. Reared on the common poplar, Populus deltoides 

 Marsh, and from Lombardy poplar, Populus nigra italica Du Roi, at 

 Ithaca, N. Y. The descriptions and drawings of the nymphal stages 

 were made from living specimens. Types in the Cornell University 

 collection. 



This species is most closely related to I. lachrymalis Fitch, from 

 which it may be distinguished by the fact that the antennae of the 

 males lack discs, the absence of the spots on the face, the less distinct 

 spots on the vertex, and the presence of a blackish line on the tibiae. 



The Egg-Parasite. On May 20 it was noticed that parasites 

 were emerging from the eggs of Idiocerus through a small round hole 

 in the bark overlying the egg-clusters. Six specimens were secured 

 of which four were females and two males. This species is apparently 

 undescribed. 



Gonaiocerus ovicenatus new species. 



Female (PL 31, Fig. 12). Liength, 1 mm., ovipositor, .36 mm. General color black, 

 the eyes dorsally and posteriorly narrowly margined with white. A broad band on 

 the vertex connecting the eyes and including the ocelli, whitish. Thorax and abdo- 

 men uniform black. Ovipositor black, distal third bent slightly downward. An- 

 tennae brownish, radicula slender, one half as long as the scape. The scape is com- 

 pressed, widened below, the articulation with the radicula marked by a whitish 

 band; pedicel obconic. The relative length of the segments of the antennse is indi- 

 cated by the following ratio: radicula and scape, 36; pedicel, 18; funicle segments 

 10, 12, 16, 15, 18, 17, 16, 16; club 40. Legs blackish, base and tip of front femora, 

 front tibiae, and tarsi of all the legs paler; terminal tarsal segments darker than basal 

 segments. Wings hyaline. Front wing one-third as wide as long. Length of 

 longest marginal ciHa about one-fifth width of the wing. 



Male (PI. 31, Fig. 11). Length, .9 mm. In color similar to the female. Whitish 

 markings on the head as in the female. Antennse brownish, thirteen segmented. 

 The relative length of the segments of the antennse is indicated by the following 

 ratio: scape 15; pedicel, 10; funicle segments, 20, 25, 24, 20, 22, 25, 25, 25, 22, 23, 22. 

 Scape short, rounded below; pedicel broadly obconic; first funicle segment 

 broader than succeeding segments; the segments of the funicle coarsely ridged 

 longitudinally. 



Described from four females and two males, reared at Ithaca, N. Y., 

 from the eggs of Idiocerus gemmisimulans Leonard and Crosby, May 

 20, 1915. Types in the Cornell University collection. 



According to Girault's table to the species of Gonatocerus (Trans. 

 Am. Ent. Soc, 37: 273), this species would run fairly well to G. maga 

 Girault, from which it may be distinguished by the antennal char- 

 acters given above. 



Our thanks are due to Professor Osborn for examining our speci- 

 mens of Idiocerus and comparing them with specimens in his collec- 

 tion. 



