RILEY NOTES ON NORTH AMERICAN MICROGASTERS. 303 



DESCRIPTIONS OF NEW SPECIES. 

 MiCROPLiTis CERATOMi^, n. sp. — Length 2.5 mm. c?$. Black; an- 

 tennae, labrum and mandibles piceous, palpi whitish ; legs red, the coxae 

 (except at apex), the basal joint of posterior tarsi and all the claws black- 

 ish ; tegulee and base of costa testaceous, wings subhjaline, the stigma 

 entirely and the veins piceous. Antenna longer than the body in both 

 sexes, joints 3-17, constricted in the middle so that each might easily be 

 counted as two joints. Mesothorax confluently punctured, a slight median 

 ridge posteriorly, a deeply impresssed groove each side, these grooves ■ 

 slightly approaching posteriorly. Metathorax coarsely reticulated, with a 

 prominent median ridge. Abdomen much shorter than the thorax, ovate, 

 basal segment vertical, finely punctured, second and following segments 

 shining, not punctured, the second segment without oblique grooves. 

 Radial vein arising from the middle of stigma, stout, forming a right 

 angle with the basal nervure of the quadrate areolet and also forming one 

 side of the areolet, beyond the areolet it is slender, a white spot on cubital 

 vein at base of areolet, the vein closing areolet exteriorly also white, the 

 side of stigma bordering the first cubital cell swollen, that bordering ra- 

 dial cell straight, apical nervures of the wing slender but distinct. 



Described from many specimens 

 which issued March 6th from co- 

 coon's formed, in September of the 

 previous year, by larvae found, in 

 Fig. 8. -Cocoons of Micropiitis cerato- Missouri, emerging from the cater- 



mii-e; a, side view; &, top view (after <^ <^ ^ 



Riley). pillar ol Cerafojm'a quadricorms. 



The cocoons, formed in irregular masses of from four to tw^enty 

 together, are of a brown color, thick, tough, coarsely ribbed lon- 

 gitudinally, and without loose threads. 



The mass of cocoons originally figured in the second volume 

 of the American Ento?/iologist, p. 128 (see Fig. 8) and which 

 was received from Mr. G. C. Brackett, Lawrence, Kans., differs 

 from those above described in the cocoons being spun regularly 

 side by side and lacking the ribs. The flies from these cocoons 

 differ only in the slightly greater size, reaching 3 mm. in length. 

 To these large specimens Mr. Cressoti has given the MS. name 

 actuosus. The same large variety, together with the compact 

 cocoons, also from C. quadricornis^ I have received from Mr. 

 A.J. Randall, Aviston, 111. It may be that this is the species 

 bred from Macrosila ^-maculaia by Mr. Emerton and figured in 

 the Ninth Ann. Report of Dr. Hayden's Survey, p. 78 1, fig. 48, 

 although the cocoon there figured is solitary. 



