353 



COKNOMYIA PALUDA Say 



Cocnomyia pallida Say, Keating 's Narrative of an Expedition to the Source of 

 the St. Peter's River, Appendix to Vol. 2, p. 339. (1824) 



larz'a. — Length, 38-45 mm. White; head and chitinized plate 

 (^n apical abdominal segment castaneous. 



Body cylindrical, slightly tapered anteriorly. Head large, conical, 

 permanently protruded, the movable portions enclosed except at apex; 

 retracted portion consisting of an arcuate dorsal plate and 4 slender 

 chitinized rods (PI. L, Figs. 3 and 4). Thoracic segments not chitin- 

 ized externally, but each with a pair of chitinized internal plates which 

 decrease in size from prothorax to metathorax, the anterior pair 

 transversely oval and occupying the greater portion of the ventral sur- 

 face; ventral hairs of moderate length. Apical abdominal segment 

 with a heavily chitinized plate, the upper margin of which is proximad 

 of the lower^ giving the segment the appearance of being obliquely 

 truncated; spiracles round, situated above middle of apical plate; 

 lower margin of plate with 2 short, stout processes (Fig. 9). 



Pupa. — Length, 30-35 mm. Dark brown, subopaque. 



Head, viewed from in front, as in Figure 8, Plate L, the antennal 

 sheath elevated, with minute thorns, the annulation indistinct. Wings 

 short, extending to apex of first abdominal segment ; apices of hind 

 tarsi scarcely extending beyond apices of wings, and closely fused to 

 the latter; thoracic spiracles sessile. Abdominal spiracles of rnoderate 

 size, their breadth less than their height; basal dorsal abdominal seg- 

 ment with 2 bristles on each side beyond middle; second and follow- 

 ing segments up to and including seventh with a complete transverse 

 series of short spines and 6 or more long bristles, the armature in- 

 creasing in strength up to seventh segment; eighth segment with a 

 group of 2-4 bristles on each side of apex above, a lateral vertical 

 series of 5 longer spines on a raised base, and a pair of stout pro- 

 tuberances, on a single base, on ventral surface at apex (Fig. 12) ; 

 postspiracular area of each segment with 2 strong bristles; ventral 

 segments with armature similar to that of dorsal but noticeably 

 stronger; apical segment as in Figure 13. 



The above descriptions were made from specimens obtained in 

 Illinois, the data being as follows: Du Quoin, August 13, 1908, turned 

 up by plow (L. M. Smith) ; larval exuvium and pupa, Chicago, Au- 

 gust, 1913 (D. K. McMillan) ; pupal exuvia, Havana, June 15, 1894 

 and Grafton, August 26, 1905. 



The larva obtained by Mr. McMillan fed upon white-grubs in 

 confinement, and as it was taken in a field where these were common 



