CHARLES W. HOOKER. 15 



an egg is laid." Dr. Felt adds that " eight to ten eggs are 

 deposited in this manner on the skin, adhering by means of 

 a cement or glue exuded at the moment of oviposition. A 

 few days later they hatch and the larvae eat their way under 

 the skin of their victim, feeding on the fatty portions of the 

 host at first, but later most of the tissues are devoured. The 

 miserable victim of these parasites drags out a weary exist- 

 ence and usually perishes in the pupal state, rarely before. 

 As a single victim will provide food for th.e development of 

 but one or two parasites, the weaker ones perish." 



Duncan's account does not quite agree with this, for he 

 writes : " The Ophionidae have a small ovipositor and deposit 

 their eggs either within caterpillars that feed on leaves in 

 broad daylight, and are unsheltered, or upon their skins. The 

 eggs are somewhat remarkable and have been carefully ex- 

 amined. They are oblong, and have a long twisted peduncle, 

 which is fixed in the skin of the victim. The young larva on 

 hatching breaks its eggshell on the side remote from the 

 peduncle, allows its body still to remain within the peduncu- 

 lated shell and thus attacks the caterpillar in safety, not en- 

 tirely leaving the eggshell till it has eaten a hole in the side 

 of its victim." Dr. Packard's observations corroborate this 

 statement for Paniscus geminatus, but Dr. Weed states that 

 " the Ophion larva is known to feed externally as the nigger 

 wasps, Bembecidce , etc., the egg being strongly fastened to 

 the skin of the victim." The views of Duncan and Weed 

 may apply to some members of the subfamily Ophioninae, but 

 do not apparently to all members of the tribe Ophionini. 

 The larva, a footless grub, feeds internally or semi-internally, 

 first on the fat bodies, later upon other tissues, and as there is 

 only enough food for one or two parasites the remainder die 

 in the struggle. The host usually lives long enough to spin 

 its cocoon and pupate, in which case the parasite does not 

 need further protection, and often does not spin a cocoon. 

 This habit is common with E. macrurus and others which prey 

 upon hosts, spinning stout cocoons, such as the saturnians, 

 etc. The parasite always causes the death of the host, and 

 sometimes the host dies before it can spin up, in which case 



TRANS. AM. KNT. SOC, XXXVIII. 



