(^ 



EXPERIMENT STATION BULLETINS. 283 



MESOCHORUS PULCHELLUS, N. SP. 



This handsome parasite (Fig. 6) belongs to- 

 the sub-family Ophioninse, as the ovipositor is 

 short, abdomen slightly compressed posteriorly 

 and petiolate, and the areolet rhomboidal. The 

 rhomboidal areolet and the exserted ovipositor 

 show that it belongs to the genus Mesochorus. 



The color is honey-yellow beautifully marked 

 with black. The antennae are long and dusky.. 

 The tip of the mandibles, compound eyes, and 

 „. „ Af i i ii t? a triangular spot containing the ocelli are black. 



Fig. 6— Mesochorus pulchellus, Fe- _,. & .^ 1 . & . . n 



male. Abdomen side view. Ine center of the mesothorax anteriorly is black 



and a dusky central line extends back from this nearly or quite to the 

 scutellum. The lateral margins of the mesonotum are black. 



The scutellum is margined with black, and a V-shape black spot marks 

 the metathorax. The tegulre are light yellow. The wings are hyaline,, 

 iridescent, stigma and nervures black. The base of the nervures are light 

 yellow. The legs are light yellow. The posterior tibias have each a 

 black spot at each end. The abdomen is spindle-shape, rather slender 

 at the base. The first segment is wholly black, triangular, narrowest 

 at the base. The second segment has a black V-shape spot at the base,, 

 while the anterior angles and a broad semicircle at its posterior margin 

 are yellow. The third segment has a broad black posterior crescent, 

 which reaches anteriorly to the angles. The three posterior segments are 

 yellowish brown, and the fifth and sixth are dusky on the posterior border. 

 The ovipositor is black. Entire under parts light yellow. Length three 

 thirty-seconds of an inch. 



The species is quite like Mesochorus Americanus, Cress. (Canadian 

 Entomologist Vol. IV, p. 23). It differs in its yellow mesothorax, dusky 

 antennas, black nervures, and stigma, black spot at base of posterior tibia?, 

 and in the black markings on the dorsal surface of the abdomen. 



THE BLACK-HEADED ISCHNOCERUS. 



The other species which we reared from the cocoons formed by parasites 

 from Eufitchia ribearia was also an Ichneumon fly. In this species the 

 ovipositor is exserted, quite long, areolet is incomplete, the parasidal 

 grooves of the mesothorax distinct, and the gostrocceli wanting. Thus this 

 species belongs to the sub-family Cryptinas. 



The areolet is absent, the first abdominal segment expanded at the 

 apex, and the spiracle is behind the middle. There are two transverse 

 carinas on the metathorax, and the abdomen is not broader than the thorax. 

 Thus our species belongs to the genus Ischnocerus. Mr. Cresson gives, 

 this as a genus with no described American species. 



