﻿126 



NINTH ANNUAL REPORT 



tion for the Advancement of Science, will correct and supplement 

 the article on the same insect published in my 5th Report : 



Our largest Neuropteroii, belonging to the family Sialidfc, is Corydalus comutus. 

 It is not uncommon in the Eastern and Middle States, and is l<nown in the Mississippi 

 Valley by the vulgar name of Hellgrammite . In the female the mandibles are quite 

 formidable, but in the male they are curiously modified, and form long, incurved, 

 smooth, prehensile organs of the form of the finger of a grain-cradle, and evidently 

 of use in enabling him to embrace his mate. The larva of this fly occurs in running 

 streams, living mostly at the bottom, and hiding under stones in the swiftest parts. 

 It has strong jaws, and in addition to the ordinary stigmata, it is furnished with two 

 sets of gills, one set lateral and filamentous, the other ventral, and each composed of a 

 sponge-like mass of short rust-brown fibres. 



[Fig. 31.] 



COBYDALua CORNUTUS:— a, a, egg-masses attached; b, one detached, showing lower surface— all rather 

 helow average size; c, a lew egsrs oi' the outer row; d, the newly-hatched larva; c, labium; 

 /, antenna; g, maxilla; h, mandible; i, tarsal claw; j, anal hooks— all enlarged. 



Its body terminates in two fleshy tubercles, each armed with a prar of hooks. It 

 is best known in the full grown condition when, in seeking for a place in which to un- 

 dergo its transformations, it travels and climbs on the shores of our rivers, and some- 

 times to long distances. Called a "crawler " by fishermen, it is greatly esteemed as 

 bait. The pupa is quiescent and formed in a cavity in the ground. The supposed eggs 

 of this insect were figured and described in the Ame7-ican Entomologist, and in the 

 Fifth Missouri Entomological Report, as oval, about the size of a radish seed, and de- 

 posited in closely set patches of fifty and upward upon reeds and other aquatic plants; 

 and they have since been frequently referred to, no one questioning the accuracy of 

 the conclusion of their discoverer, the late B. D. Walsh. 



About the middle of last July, in sailing up the Mississippi river between Bush- 

 berg and St. Louis, my attention was attracted by sundry white splashes on the leaves 

 of various plants that overhung the water; which splashes looked, at a distance, 

 not unlike the droppings of some large bird. Approaching more closely to them, how- 



