February, '15] FELT: :MYC0DIPL0SIS MACGREGORI N. SP. 



149 



Fig. 9. Polyhedra of a Gipsy moth caterpillar fed Nun wilt. 



(Average size 2.5/x and 2.1^1) 

 Fig. 10. Polyhedra of a Gipsy moth fed Phryganidia wilt. 



(Average size 2.15^ and 2.1^) 

 Fig. 11. Polyhedra of an Apple tent caterpillar fed Gipsy moth wilt. 



(Average size 2.35^ and 2.2^1) 

 Fig. 12. Polyhedra of a Gipsy moth caterpillar. 



(Showing two extremes) 

 Fig. 13. Polj^hedra of an Apple tent caterpillar. 



(Showing two extremes) ^ 

 Fig. 14. Polyhedra of a Forest tent caterpillar. 



(Showing two extremes) 



Drawn by camera lucida. (Ocular 6, Oil immersion t2, tube length 160 mm.) 



MYCODIPLOSIS MACGREGORI N. SP. 



By E. P. Felt, Albany, N. Y. 



The small iriclge described below was reared July 16, 1914, by 

 Mr. E. A. MacGregor, Batesburg, S. C, from red spider on cotton, 

 and at the tim.e of rearing it was supposed to be identical with Arthroc- 

 nodax Carolina Felt. This new species runs in our keys to M: tsugce 

 Felt, from which it may be easily separated by the equal and shorter 

 stems of the fifth antennal segment and marked differences in the male 

 genitalia. 



Male. Length 1.2 mm. Antennae one-fourth longer than the body, sparsely 

 haired; fuscous yellowish; 14 segments, the fifth having the two portions of the stem 

 nearly equal, each with a length one-half greater than its diameter; terminal seg- 

 ment with the basal enlargement oblate, the basal portion of the stem slender and 

 with a length about twice its diameter, the distal enlargement stout, with a length 

 one-half greater than its diameter and roundly tapering to an irregular, finger-hke 

 process less than one-half the length of the distal enlargement. Palpi; first segment 

 irregular, the second with a length one-haK greater than its diameter, the third one- 

 half longer than the second, more slender, the fourth nearly twice the length of the 

 third and somewhat compressed. Mesonotum fuscous yellowish. Scutellum and 

 postscutellum yellowish. Abdomen light fuscous yellowish, the genitalia slightly 

 fuscous. Wings hyaline. Halteres whitish transparent. Coxae and femora mostly 

 pale yellowish, the tibise slightly darker and the tarsi a light straw; claws slender, 

 evenly curved, the anterior and mid claws unidentate; pulvilli reduced, about two- 

 thirds the length of the claws. Genitalia; basal clasp segment long, slender; terminal 

 clasp segment rather short, stout, nearly straight, the dorsal plate short, deeply 

 and roundly emarginate, the lobes tapering to a broadly roundly apex; ventral plate 

 moderately long, tapering at the basal third, the distal portion of the sides nearly 

 parallel, the apex broadly rounded and with two pairs of large, latere- posterior 

 setae; style long, slender, acute. Type Cecid. a2601. 



