Entomology of the Illinois River. 17^ 



where the largest numbers of the Hydrocampa occurred, 

 flitting about in an investigating way over the floating 

 leaves, often disappearing in the water beneath the 

 edge of one and soon reappearing at some other point 

 of its margin and flying to another. This Cryptus has, 

 in fact, been previously bred in Florida, March 26, from 

 a Hydrocampa on water lil^-, supposed to be ohliteralis.*' 



Egg [Fig. 8, 9]. — Length 6 mm., width 4 mm. Oval, 

 amber-colored, flattened, one surface broadly gummed to 

 the leaf, the other finely longitudinally^ wrinkled, a longi- 

 tudinal elevated ridge at middle. Described from examples 

 laid in a band on the under side of a floating leaf of 

 Potamogeton nutans, near and parallel to its margin. 



Larva^ first stage. — This does not differ markedly in sur. 

 face, structures, or color, from the mature larva; the setae 

 are more conspicuous, especially posteriorly, and the 

 ocelli are closely approximate, the lower three in a solid 

 oblong black dash, with the other two just above. 



Larva, mature [Fig. 10-12].— Length 13-14 mm., width 

 2 mm. Fusiform subcylindrical, slightly depressed, broad- 

 est at middle, uniform dirty whitish. Surface subopaque, 

 microscopically granulate or scabrous, more noticeably 

 so on the anterior part of the thorax. 



Head rather small, light brownish j'ellow; Y-mark 

 narrowly darker, bordered each side with whitish; a 

 lateral brown stripe from base of head nearly to ocelli; 

 labrum deeply and rather acutely emarginate at middle; 

 mandibles sharply toothed ; sutures beneath more or 

 less darker; first antennal joint truncate-conic, whitish, 

 second slender, very pale yellowish, tipped with a seta 

 and three minute articles, the middle one of which is 

 deeply cleft; ocelli five, four in a slight curve just back 

 of base of antenna, the middle ones contiguous, their 

 pigment spots large and confluent, the upper one 

 smaller and more isolated, behind it and similar to it, 

 the fifth one. 



*"Bred Parasitic Hjinenoptera in the Collection of the U. S. National Museumm/* 

 Insect Life. Vol. III., p. 154, 



