200 



PROCEEDINGS OF THE NATIONAL MUSEUM. 



vol. 48. 



Fig. 2.— Cephalic horns of pupa of Ctenodactylo 

 myia •watsoni. 



of the Agricultural Experiment Station. The galls are abundant and 

 irregularly clustered upon the small piece of leaf accompanying the 

 specimens. The insects evidently transform within the galls, since 

 whitish exuviae are to be found projecting from the deformations. 



Gall. — Diameter, 3 mm., circular, blisterlike, dark green, with a 

 slight, darker, median nipple. The gall shows about equally upon 



both sides of the leaf. 



Larva. — Length, 3 mm., yel- 

 lowish, the segmentation dis- 

 tinct and tapering toward the 

 posterior extremity. Head 

 and breastbone indistinct in 

 the one specimen before us. 



Exuviae. — Length, 3 mm., 

 whitish transparent. Anten- 

 nal cases extending nearly to 

 the base of the abdomen, wing 

 pads to the third abdominal 

 segment, and the leg cases 

 about to the sixth abdominal 

 segment; cephalic hornslarge, 

 chitinous, approximate, the lateral margins strongly serrate and 

 tapering irregularly to the median line, the abdominal segments each 

 with a transverse row of about 8 chitinous spines near the anterior 

 third, the number being reduced to about 4 on the penultimate 

 segment; terminal segment bilobed. 



Pupa. — Length, 3 mm., moderately stout and variably yellowish 

 or dark brown, dependent upon the devel- 

 opment, the external structures as in the 

 exuviae. 



Female. — Length, 3 mm. Eyes confluent. 

 Antennse nearly as long as the body, sparsely 

 haired, light brown; 14 segments, the third 

 and fourth fused, the fifth with a stem about 

 one-fifth the length of the subcylindric basal 

 enlargement, which latter has a length three 

 and one-half times its diameter and sparse 

 subbasal and subapical whorls of moderately 

 stout setse; cireumnli near the basal third 

 and apically; terminal segment produced, 

 apically with a finger-like process about one-third the length of the 

 cylindrie basal enlargement, which latter has a length three times its 

 diameter. Palpi ; first segment with a length over twice its diameter, 

 the second as long as the first, somewhat stouter, the third more than 

 twice the length of the second, slender; mouth parts slightly produced, 

 with a length about one-fourth the diameter of the head. Mesonotum 



Fig. 3.— Middle claw of male of 



CTENODACTYLOMYIA WATSONI. 



