102 NEW YORK STATE MUSEUM ' 



Op hi on fuliginipennis Felt, which belongs in a dif- 

 ferent group. Erem. macrurus may be separated from 

 E r e m . a r c t i a e by its larger size, by the fulvous tinge of the 

 wings and veins, by the second discoidal nervure being nearly 

 twice the length of the first, and by there being from 13 to 15 

 hooks on the hind wings. Other differences are detailed in the 

 description of Erem. arctiae. 



Habits and life history. This species is an active, diurnal insect, 

 being rarely if ever attracted to lights. It is the one most com- 

 monly bred from the large saturnians, and is frequently referred 

 to as a parasite of one or more of them. Its egg-laying habits 

 and life history, so far as known, have been described in a pre- 

 ceding paragraph. It has also been recorded as bred from some 

 of the arctians, but it is probable that some of these records really 

 pertain to Erem. arctiae. Dr C. M. Weed has recorded an 

 instance in which 30 out of 50 pupae of Samia Columbia 

 Smith were parasitized by this insect. The unusual abundance of 

 C a 1 1 o s a m i a p r o m e t h e a Dr. is recorded in Insect Life, 

 2:383, and also the interesting fact that fully two thirds of the 

 pupae harbored this parasite. The observations of l)r Riley show 

 that tills insect usualh'' emerges in the spring, though occasionally 

 individuals come forth in the autumn. 



This parasite has been reared from the following insects : I s i a 

 Isabella Abb. & Sm., Philosamia cynthia Drury, 

 C a 1 1 o s a m i a p r o m e t h e a Drury, Samia Columbia 

 Smith, Samia c e c r o p i a Linn., Telia polyphemus 

 Oram., Automeris io Fabr. and Apatelodes torre- 

 facta Abb. & Sm. 



Description. Fulvo-ferruginous, stigma almost obsolete; mar- 

 ginal nervure sinuate, thickened toward the stigma; size large; 

 body 31 to 38 mm long ; wing spread 43 to 56 mm. Head small, 

 antennae nearly as long as the body; ocelli prominent, black; 

 head yellowish posteriorly; eyes black, rather small; mandibles 

 bidentate, tipped Avith black. Mesothorax convex; scutellum and 

 postscutellum prominent; anterior portion of metathorax de- 

 pressed; posterior portion rugose, limited anteriorly by a trans- 

 verse carina; lateral carinae present. Wings hyaline; marginal 

 nervure thickened, sinuate near the small stigma ; cubitodiscoidal 

 nervure never appendiculate, usually strongly sinuate; third dis- 



