NORTH AMERICAN GEOTRUPINAE — HOWDEN 257 



N. C: Three second-stage, one third-stage larvae collected from cage 

 on July 1, 1952; two second-stage larvae collected from cage Aug. 4, 

 1952; and five third-stage larvae collected in August and preserved on 

 Sept. 15, 1952 



Third-stage larvae of G. hornii differ from Ritcher's description 

 (1947, pp. 6-7) of G. hlackhurnii excrementi in the following respects. 



Maximum width of head capsule 4.0 to 4.5 mm. Frons on each side 

 with 1 posterior frontal seta, 2 or 3 setae in each anterior angle, 1 ex- 

 terior frontal seta and 1 or 2 anterior frontal setae. Antenna fairly 

 long, the length of the second segment equal to or slightly longer than 

 that of the first segment. Third segment greatly reduced in diameter 

 (pi. 7, fig. 7), only half as long as the second segment. Mandibles and 

 maxillae not differing in any respect from Eitcher's description, except 

 that the 2 or 3 stridulatory teeth on the posterior margin of the palpifer 

 of hlackhurnii are usually lacking in hornii. Hypopharynx (pi. 8, 

 fig. 8) with 2 asymmetrical oncyli which are generally narrower than 

 that of hlackhurnii. Before the h3^popharynx is a row of 20 or more 

 sensilla on each side united medially. At the midline, anteriorly, is a 

 clump of 6 or 7 sensilla and, posteriorly, 2 setae. Glossa slightly 

 emarginate. Epipharynx (pi. 8, fig. 7) with tormae united mesaUy, 

 very similar to hlackhurnii. Anterior and posterior epitormae of equal 

 length. Anterior to the pedium is a row of 7 or 8 setae. In hlackhurnii 

 there are about 6 setae in the same area, in an uneven row. 



Body less swollen posteriorly than hlackhurnii but otherwise quite 

 similar. Endoskeletal figure (pi. 7, fig. 15) of anal segment not as 

 constricted as that of hlackhurnii, quite similar to that figured for 

 ulkei hj Eitcher (1947, p. 27, fig. 44). Dorsal annulets of abdominal 

 segments 7 and 8 lacking the transverse patch of long setae present in 

 hlackhurnii, otherwise setal patterns are quite similar. 



Legs 3-segmented, prothoracic and mesothoracic legs rather long, 

 metathoracic legs reduced in size. Nine to 11 stridulatory teeth on 

 the inner surface of the fused trochanter-femur of metathoracic legs 

 and 5 to 8 small teeth on the inner surface of the tibiotarsus. Tips of 

 all legs with a circle of setae around a small tubercle (pi. 7, fig. 10) 

 which lacks the small brownish claw present in hlackhurnii. 



Second instar maximum width of head capsule 3.2 to 3.5 mm. No 

 other morphological difference noted to distinguish second instar from 

 the third-stage larva. 



Specimens examined: 114 males, 131 females, 22 not sexed. 



CANADA 



NO EXACT LOCALITY: 1 specimen. No data. 



NEWFOUNDLAND: 1 male, 3 females. Nicholasville, Romaine Brook; (1) 

 July. 



