16 AMERICAN HYMENOPTERA. 



the parasite usually crawls to some protected place and spins 

 a cocoon of its own. Thus the cocoons of E. purgatus are 

 often found in the soil or under some shelter where its host 

 has transformed, and it is probable that such is the case with 

 all species infesting larvae that do not spin stout cocoons be- 

 fore pupating. The cocoon when spun is compressed oval, 

 made of fine silk threads tightly glued together with a fluid 

 which sometimes gives it a dark-brown color. The color 

 varies somewhat, but is usually dirty brown or some shade 

 of brown, often with a median transverse, or rarely with a 

 lateral longitudinal band. The interior is often of a lighter 

 color. The mature larvae of E. macrurus, at least, pass the 

 winter within the cocoon, pupating in early spring. Nothing 

 is known of the food, mating habits, etc., of the adults, but 

 it is possible that they feed on decaying animal and vegetable 

 matter, since Dr. Ashmead states that they are attracted to 

 such substances. Morley states that " many kinds of Ophion- 

 inse, including the big red Ophion luteus, are freely attracted 

 by sugar. No insect is more fond of sweets, and none more 

 indifferent to bright colored flavorless objects than the Ich- 

 neumons. Ophions and Ichneumons will not return to 

 flowers if frightened away." The common Ophions may 

 often be taken around evergreens where they seem to be 

 attracted by the resinous juices. 



The literature relating to their biology is as follows : 



Trouvelot, Am. Nat., I, pp. 89-91, f. 1 1867. 



Riley, Fourth Ann. Rept. Ins. Missouri, p. 107, ff. 37, 38 1872. 



Vollenhoven, Pinacographia, p. 44, PI. XXVIII, ff. 1-6 1880. 



Bridgman and Hitch, The Entomologist, XIII, pp. 28-32, PI. I....1880. 

 " Idem, XVIII, pp. 122-128, No. 5, PI. II 1884. 



Duncan, Transformations of Insects, pp. 2-3 1882. 



Lintner, Ins. N. Y., First Rept., pp. 103-110 (parasitic on Nephe- 



lodes violatts Gn.) 1882. 



Packard, Third Rept. U. S. Ent. Comm., p. 128, PI. II, f. 5. 



(Larva of O. purgatus from cutworms) 1883. 



Jack, Can. Ent., XVII, p. 21 1885. 



Webster, F. M., Rept. U. S. Dept. Agr., 1884, p. 289 (parasitic 



on Nematus) 1889. 



Cresson, Syn. Hym. N. A., pp. 40-43, 200 1887. 



Riley, Ins. Life, III, pp. 55-276 (feeding habits of lairvae, ex- 

 ternal) 1891. 



